01851nas a2200253 4500008004100000022001400041245009500055210006900150260007300219300001400292490000800306520089500314653003401209653003001243653003301273653002501306653001601331100002001347700002401367700002401391700002401415700003301439856012501472 2012 eng d a0169-433200aEnhancing the hydrogen storage capacity of Pd-functionalized multi-walled carbon nanotubes0 aEnhancing the hydrogen storage capacity of Pdfunctionalized mult aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB a3405-34090 v2583 a

We demonstrate that the hydrogen storage capacity of multi-walled carbon nanotubes can be enhanced by polyvinylpyrrolidone functionalization. The polyvinylpyrrolidone acts as a stabilizing agent for Pd-nanoparticles, reduces their size and facilitates their uniform and enhanced loading onto multi-walled carbon nanotubes. According to sorption studies, the polyvinylpyrrolidone capping and consequent nanostructural modification enables 2.3 times more hydrogen adsorption than mere Pd-functionalization of multi-walled carbon nanotubes. Corresponding morphological changes before and after polyvinylpyrrolidone capping, characterized using Raman Spectroscopy, X-ray diffraction, TEM and thermal analysis techniques, are also presented. The results contribute towards increasing the efficiency of hydrogen based sustainable energy sources. (C) 2011 Elsevier B.V. All rights reserved.

10aHydrogen based energy sources10aHydrogen storage capacity10aMultiwalled carbon nanotubes10aPd functionalization10aPVP capping1 aSingh, Priyanka1 aKulkarni, Mukta, V.1 aGokhale, Suresh, P.1 aChikkali, Samir, H.1 aKulkarni, Chandrashekhar, V. uhttps://library.ncl.res.in/content/enhancing-hydrogen-storage-capacity-pd-functionalized-multi-walled-carbon-nanotubes-002325nas a2200241 4500008004100000022001400041245010100055210006900156260006900225300001000294490000800304520143300312653001201745653003401757653002301791653003901814653001201853653002201865100001801887700002501905700002401930856012901954 2014 eng d a0010-854500aContemporary avenues in catalytic P-H bond addition reaction: a case study of hydrophosphination0 aContemporary avenues in catalytic PH bond addition reaction a ca aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcAPR a52-730 v2653 a

Remarkable advances and current state-of-the-art developments in catalytic hydrophosphination of alkenes and alkynes are reviewed. The challenges in constructing a C P bond with a special emphasis on metal catalysed (asymmetric) hydrophosphination are highlighted. Only those systems that unambiguously proceed via P H bond addition across a C-C/X (X = O, N, S) multiple bond have been covered in this overview. Reviewed examples support the assumption that either strongly chelating ligands or reaction products that act as ligands, enhance the rate of hydrophosphination. The asymmetric variant of this transformation allows installation of p-chiral [enantiomeric excess (ee) up to 82%] as well as C-chiral (ee up to 99%) centres. The limited spectroscopic, mechanistic data and OFT calculations point at two distinctly different mechanisms. In case of hydrophosphination, the metal undergoes oxidative addition and reductive elimination steps (in general), thus changing the oxidation state from M(0) to M(II) and back to M(0). Whereas in asymmetric hydrophosphination it is proposed that the oxidation state of the metal remains unaltered throughout the catalytic cycle. The examples described in this overview showcase the real power of catalytic hydrophosphination in constructing various phosphorus compounds, which may initiate a new era in organo-phosphorus chemistry. (C) 2014 Elsevier B.V. All rights reserved.

10aAlkynes10aAsymmetric hydrophosphination10aHydrophosphination10aMetal catalyzed hydrophosphination10aOlefins10aP-H bond addition1 aKoshti, Vijay1 aGaikwad, Shahaji, R.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/contemporary-avenues-catalytic-p-h-bond-addition-reaction-case-study-hydrophosphination-001675nas a2200229 4500008004100000022001400041245008100055210006900136260006900205300000900274490000800283520084100291653003201132653002701164653002501191653002501216653001201241100002401253700003001277700002301307856011501330 2014 eng d a0010-854500aHybrid diphosphorus ligands in rhodium catalysed asymmetric hydroformylation0 aHybrid diphosphorus ligands in rhodium catalysed asymmetric hydr aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcMAR a1-150 v2623 a

This review aims to illustrate recent advances in the application of hybrid diphosphorus ligands for the Rh catalysed hydroformylation of alkenes, discussing the most prevalent classes of hybrid systems, i.e. phosphine-phosphinite, phosphine-phosphonite, phosphine-phosphite, phosphite-phosphoramidite and phosphite-phosphoramidite and comparing their performance with relevant C-2 symmetric counterparts. In order to introduce the field and put the results in context, a short overview on Rh hydroformylation is provided. Available spectroscopic (in situ) data on the coordination modes of hybrid phosphorus ligands and the catalytic performance of these systems in asymmetric hydroformylation of vinyl arenes are reported. Potential avenues for future research are shortly discussed. (C) 2013 Elsevier B.V. All rights reserved.

10aAsymmetric hydroformylation10aCatalyst resting state10aHybrid ligand design10aIn situ spectroscopy10aRhodium1 aChikkali, Samir, H.1 avan der Vlugt, Jarl, Ivar1 aReek, Joost, N. H. uhttps://library.ncl.res.in/content/hybrid-diphosphorus-ligands-rhodium-catalysed-asymmetric-hydroformylation-001479nas a2200121 4500008004100000245006000041210005900101260000800160520104600168100002401214700002601238856009301264 2014 eng d00aIsohexide-diacetal based polymers and a process thereof0 aIsohexidediacetal based polymers and a process thereof cNOV3 a

The present invention discloses isohexide based compounds and their polymers which are derived from renewable resources and are potentially degradable. Also disclosed herein is the synthesis of isohexide based monomers and their polymers from renewable resources which are potentially degradable. Further, the present invention disclose a process for the synthesis of isohexide based copolymers via copolymerization of isohexide based monomers and long chain diols, which are degradable. (FR)Cette invention concerne des composés à base d'isohexide et leurs polymères qui sont dérivés de ressources renouvelables et sont potentiellement dégradables. Cette invention concerne également la synthèse de monomères à base d'isohexide et leurs polymères à partir de ressources renouvelables qui sont potentiellement dégradables. Un procédé de synthèse de copolymères à base d'isohexide par copolymérisation desdits monomères à base d'isohexide et de diols à chaîne longue, qui sont dégradables, est en outre décrit.

1 aChikkali, Samir, H.1 aRajput, Bhausaheb, S. uhttps://library.ncl.res.in/content/isohexide-diacetal-based-polymers-and-process-thereof01821nas a2200229 4500008004100000022001400041245010000055210006900155260006700224300000800291490000700299520096500306653002201271653003101293653002301324653002301347653001901370100002501389700002401414700002401438856012901462 2014 eng d a0887-624X00aPd-Phosphinesulfonate bravely battles the ``vinyl halide insertion copolymerization'' barricade0 aPdPhosphinesulfonate bravely battles the vinyl halide insertion  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcJAN a1-60 v523 a

This overview provides insights into the current state-of-the-art solutions to insertion copolymerization of functional olefinic monomers. The challenges in insertion copolymerization of functional olefinic monomers, with a special emphasis on vinyl halides, are highlighted. The crucial design of the Pd-phosphinesulfonate [Pd(PO)] enables up to 3.6 mol % incorporation of vinyl fluoride (VF) in an ethylene-VF copolymerization reaction. In a significant development, insertion copolymerization of industrially relevant functional olefin, that is, vinyl chloride (VC), was unambiguously ascertained, and a detectable amount of VC (0.4 mol %) was incorporated (at the chain end). In a detailed investigation, the in situ existence of (PO)PdH species during the polymerization was revealed, and it was demonstrated that these are indeed responsible for VC incorporation. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1-6

10afunctional olefin10ainsertion copolymerization10apalladium catalyst10aphosphinesulfonate10avinyl chloride1 aGaikwad, Shahaji, R.1 aDeshmukh, Satej, S.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/pd-phosphinesulfonate-bravely-battles-vinyl-halide-insertion-copolymerization-barricade-001363nas a2200181 4500008004100000022001400041245004400055210004400099260011000143300001400253490000700267520074600274100001901020700002001039700002201059700002401081856007601105 2014 eng d a1463-926200aSustainable polyacetals from isohexides0 aSustainable polyacetals from isohexides aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAUG a3810-38180 v163 a

A single step synthetic protocol to access a small family of renewable diacetals was established. The resultant chiral diacetals are valuable building blocks in pharmaceuticals and materials science. To demonstrate their synthetic competence, isohexide-diacetals (2a-c) were subjected to acetal metathesis polymerization and the corresponding polymers (poly2a-c) were isolated as white solids with molecular weights in the range 3200-27 600 (g mol(-1)). The semi-crystalline polymers displayed glass transition temperatures between 38-65 degrees C and melting temperatures in the range 103-156 degrees C. The isohexide derived polyacetats are stable under practical washing and rinsing conditions but degrade in slightly acidic media.

1 aRajput, B., S.1 aGaikwad, S., R.1 aMenon, Shamal, K.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/sustainable-polyacetals-isohexides-001889nas a2200181 4500008004100000022001400041245012600055210006900181260007100250300001400321490000700335520114600342100002201488700002101510700002401531700002401555856012801579 2015 eng d a0276-733300aHighly enantioselective Pd-catalyzed synthesis of P-stereogenic supramolecular phosphines, self-assembly, and implication0 aHighly enantioselective Pdcatalyzed synthesis of Pstereogenic su a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT a4802-48050 v343 a

Metal-catalyzed asymmetric addition of a secondary phosphine to an aryl halide is one of the most efficient and reliable approaches for the construction of enantiopure carbon phosphorus bonds. An isolated Pd(II) complex (5) catalyzes the carbon phosphorus coupling reaction between tolylphenylphosphine (la) and 3-iodophenylurea (2b), which proceeds with an unprecedented enantiomeric excess (ee) of 97%. The generality of the strategy has been demonstrated by preparing a small library of a new class of P-stereogenic phosphines with an in-built hydrogen bonding motif for the first time. The P-stereogenic phosphines self-assemble on a metal template via deliberately installed hydrogen-bonding motifs and mimic the bidentate ligand coordination. Interestingly, when it was employed in asymmetric hydrogenation, the supramolecular phosphine {1-(3-(phenyl(o-toly)phosphanyl)pheny)ureal} (6b) produced the corresponding hydrogenated product with the highest enantiomeric excess of 99% along with excellent conversion, demonstrating the potential of these enantioenriched P-chirogenic supramolecular phosphines in asymmetric catalysis.

1 aKoshti, Vijay, S.1 aMote, Nilesh, R.1 aGonnade, Rajesh, G.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/highly-enantioselective-pd-catalyzed-synthesis-p-stereogenic-supramolecular-phosphines-101458nas a2200217 4500008004100000022001400041245013200055210006900187260007500256300001400331490000600345520063000351653001200981653002000993653002101013653001801034653001201052100002201064700002401086856013001110 2015 eng d a1867-388000aHighly regioselective isomerizing hydroformylation of long-chain internal olefins catalyzed by a rhodium bis(phosphite) complex0 aHighly regioselective isomerizing hydroformylation of longchain  aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcNOV a3468-34710 v73 a

The single-step synthesis, coordination behavior, and application of a bis(phosphite) ligand in the isomerizing hydroformylation of internal olefins was investigated. Interestingly, high-pressure NMR spectroscopy investigations revealed unexpected inequivalency of the two phosphorus nuclei, which display bisequatorial coordination of the bis(phosphite) ligand in a trigonal bipyramidal rhodium complex. Upon employment in the isomerizing hydroformylation of the exceedingly challenging plant oil derived substrate methyl oleate, the bis(phosphite) rhodium complex revealed an unprecedented linear selectivity of 75%.

10aalkenes10abis(phosphite)s10aHydroformylation10aisomerization10aRhodium1 aPandey, Swechchha1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/highly-regioselective-isomerizing-hydroformylation-long-chain-internal-olefins-catalyzed-001755nas a2200193 4500008004100000022001400041245008200055210006900137260007100206300001200277490000600289520103400295100002501329700002401354700002401378700002401402700002401426856011101450 2015 eng d a2161-165300aInsertion copolymerization of difunctional polar vinyl monomers with ethylene0 aInsertion copolymerization of difunctional polar vinyl monomers  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP a933-9370 v43 a

A single-step synthesis, structural characterization and application of a neutral, acetonitrile ligated, palladium-phosphinesulfonate complex [{P<\^>O}PdMe(L)] (P<\^>O = K-2-P,O Ar2PC6H4SO2O with Ar = 2-MeOC6H4; L = CH3CN) (3) in coordination/insertion copolymerization of ethylene with difunctional olefin is investigated. In a significant development, complex 3 was found to catalyze insertion copolymerization of industrially relevant 1,1-disubstituted difunctional vinyl monomers for the first time. Thus, insertion copolymerization of ethyl-2-cyanoacrylate (ECA or super glue) and trifluoromethyl acrylic acid (TFMAA) with ethylene produced the corresponding copolymers with 6.5% ECA and 3% TFMAA incorporation. Increasing the concentration of difunctional olefins led to higher incorporation but at the expense of lower activities. These observations indicate that complex 3 tolerates difunctional vinyl monomers and provides direct access to difunctional polyolefins that have not been attempted before.

1 aGaikwad, Shahaji, R.1 aDeshmukh, Satej, S.1 aGonnade, Rajesh, G.1 aRajamohanan, P., R.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/insertion-copolymerization-difunctional-polar-vinyl-monomers-ethylene-100603nas a2200169 4500008004100000245007700041210006900118260000800187300001500195490000700210100002200217700002500239700002300264700002400287700002400311856009800335 2016 eng d00aImpact of modular substitution on crystal packing: the tale of two ureas0 aImpact of modular substitution on crystal packing the tale of tw cAUG a 7078-70940 v181 aKoshti, Vijay, S.1 aThorat, Shridhar, H.1 aGote, Ravindra, P.1 aChikkali, Samir, H.1 aGonnade, Rajesh, G. uhttps://library.ncl.res.in/content/impact-modular-substitution-crystal-packing-tale-two-ureas00588nas a2200133 4500008004100000022002000041245010400061210006900165250002400234260001500258100002400273700002500297856013200322 2016 eng d aWO2016038631 A100aMetal phosphine-sulfonate acetonitrile complex for insertion copolymerization of functional olefins0 aMetal phosphinesulfonate acetonitrile complex for insertion copo aC07F9/50, C07F15/00 aIndiacMAR1 aChikkali, Samir, H.1 aGaikwad, Shahaji, R. uhttps://library.ncl.res.in/content/metal-phosphine-sulfonate-acetonitrile-complex-insertion-copolymerization-functional-olefins02037nas a2200277 4500008004100000022001400041245006600055210006600121260007500187300001400262490000800276520113600284653001801420653002401438653001401462653001501476653002301491100002601514700001901540700001901559700002201578700002201600700002001622700002401642856009301666 2016 eng d a1022-135200aSynthesis of renewable copolyacetals with tunable degradation0 aSynthesis of renewable copolyacetals with tunable degradation aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJUN a1396-14100 v2173 a

Acetal metathesis copolymerization (AMCP) of renewable isohexide diacetals and aliphatic long-chain diacetals is reported and access to a small family of copolyacetals has been established. Crucial 1-2D NMR and MALDI-ToF-MS findings unambiguously confirm the existence of a copolymeric structure. In a stark contrast to the earlier reported isohexide-polyacetals, the current copolyacetals reveal very slow degradation. Hydrolytic degradation of copolyacetal pellets is extremely slow at pH 7, whereas only 30% degradation over a period of 15 d is observed in 9 M hydrochloric acid solution. GPC investigations reveal that with increasing chain-length the rate of degradation reduces, whereas copolyacetals with short-chain aliphatic segments display a faster degradation profile. The reduced rate of degradation can be attributed to the hydrophobic nature of long-chain acetal segments. In situ NMR spectroscopy reveals the existence of formates, hemiacetals, and diols as degradation products. Thus, the rate of degradation can be tuned by the judicious choice of isohexide-diacetal and linear-diacetals in a copolyacetal.

10acopolyacetals10adegradable polymers10adiacetals10aisohexides10arenewable polymers1 aRajput, Bhausaheb, S.1 aChander, Umesh1 aArole, Kailash1 aStempfle, Florian1 aMenon, Shamal, K.1 aMecking, Stefan1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/synthesis-renewable-copolyacetals-tunable-degradation02517nas a2200205 4500008004100000245015200041210006900193260000800262300001600270490000700286520173400293100002102027700001702048700002302065700002502088700002202113700002402135700002402159856012802183 2017 eng d00aH-Bonding assisted self-assembly of anionic and neutral ligand on metal: a comprehensive strategy to mimic ditopic ligands in olefin polymerization0 aHBonding assisted selfassembly of anionic and neutral ligand on  cOCT a12448-124560 v563 aSelf-assembly of two neutral ligands on a metal to mimic bidentate ligand coordination has been frequently encountered in the recent past, but self-assembly of an anionic ligand on a metal template alongside a neutral ligand remains an elusive target. Such a self-assembly is hampered by additional complexity, wherein a highly negatively charged anion can form intermolecular hydrogen bonding with the supramolecular motif, leaving no scope for self-assembly with neutral ligand. Presented here is the self-association of anionic ligand 3-ureidobenzoic acid (2a) and neutral ligand 1-(3-(diphenylphosphanyl)phenyl)urea (1a) on a metal template to yield metal complex [{COOC6H4-NH(CO)NH2}{Ph2PC6H4NH(CO)NH2}PdMeDMSO] (4a). The identity of 4a was established by NMR and mass spectroscopy. Along the same lines, 3-(3-phenylureido)benzoic acid (2b) and 1-(3-(diphenylphosphanyl)phenyl)-3-phenylurea (1b) self-assemble on a metal template to produce palladium complex [{COOC6H4NH(CO)NHPh}{Ph2PC6H4NH(CO)NHPh}PdMePy] (5c). The existence of 5c was confirmed by Job plot, 1-2D NMR spectroscopy, deuterium labeling, IR spectroscopy, UV-vis spectroscopy, model complex synthesis, and DFT calculations. These solution and gas phase investigations authenticated the presence of intramolecular hydrogen bonding between hydrogen's of 1b and carbonyl oxygen of 2b. The generality of the supramolecular approach has been validated by preparing six complexes from four monodentate ligands, and their synthetic utility was demonstrated in ethylene polymerization. Complex 4a was found to be the most active, leading to the production of highly branched polyethylene with a molecular weight of 55700 g/mol and melting temperature of 112 degrees C.1 aMote, Nilesh, R.1 aPatel, Ketan1 aShinde, Dinesh, R.1 aGaikwad, Shahaji, R.1 aKoshti, Vijay, S.1 aGonnade, Rajesh, G.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/h-bonding-assisted-self-assembly-anionic-and-neutral-ligand-metal-comprehensive-strategy01629nas a2200157 4500008004100000245006000041210006000101260000800161300001400169490000600183520112100189100002201310700002301332700002401355856009201379 2017 eng d00aIsomerizing hydroformylation of cashew nut shell liquid0 aIsomerizing hydroformylation of cashew nut shell liquid cOCT a3997-40040 v93 aA small library of bisphosphorus ligands was evaluated in the rhodium-catalyzed isomerizing hydroformylation (I-HF) of cashew nut shell liquid (CNSL). The rhodium complex of 1,2-bis((di-tert-butylphosphanyl)methyl)benzene (BDTBPMB; L4) outperformed the other bisphosphite and bisphosphine ligands and unveiled a moderate selectivity of 28% and 50% in the I-HF of CNSL monoene and methoxy-protected monoene, respectively. The resultant aldehyde 16-(3-methoxyphenyl)hexadecanal P1 was isolated and its identity was fully established. Application of bis-phosphine ligand L4 in the I-HF of highly challenging CNSL cardanol (S3) and methoxy-protected CNSL cardanol yielded a linear selectivity of 74%, although with reduced conversion. To demonstrate the synthetic utility of our strategy, the obtained aldehyde (derived from S3) was subjected to hydrogenation and the resultant 3-(16-hydroxyhexadecyl) phenol (P8) was isolated in 89% isolated yield. High-pressure NMR investigation revealed selective formation of a bis-equatorial BDTBPMB-rhodium complex, which might be responsible for the excellent linear selectivity.1 aPandey, Swechchha1 aShinde, Dinesh, R.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/isomerizing-hydroformylation-cashew-nut-shell-liquid02658nas a2200205 4500008004100000245010100041210006900142260000800211300001400219490000700233520190800240100002502148700002402173700002202197700002002219700002402239700003502263700002402298856013002322 2017 eng d00aReactivity of difunctional polar monomers and ethylene copolymerization: a comprehensive account0 aReactivity of difunctional polar monomers and ethylene copolymer cAUG a5748-57580 v503 aA comprehensive picture of insertion of 1,1-disubstituted difunctional olefins, their ability to double the functional group density at the same level of incorporation as that of monofunctional olefin, and copolymerization with ethylene has been demonstrated. Exposure of a palladium complex [{P boolean AND O}PdMe(L)] (P boolean AND O = kappa(2)-P,O-Ar2PC6H4SO2O with Ar = 2-MeOC6H4.; L = C2H6OS) to methyl 2-acetamidoacrylate (MAAA) revealed slight preference for 1,2-insertion over 2,1-insertion (1.0:0.7). In contrast, insertion of electron-deficient 2-(trifluoromethyl)acrylic acid (TFMAA) unveiled selective 2,1-insertion {via [(P boolean AND O)PdC5H6F3O2] (11)1. The unstable intermediate 11 undergoes beta-hydride and beta-fluoride elimination to produce subsequent insertion and elimination products. The identity of elimination products (E/Z)-2-trifluoromethyl)but-2-enoic acid [17(E/Z)] and 2-(difluoromethylene)butanoic acid (13) was fully established by 1-2D NMR spectroscopy. These insertion experiments, taken together with insertion rates, suggest that MAAA and TFMAA. are amenable to insertion. Polymerization of ethylene with MAAA, TFMAA, acetamidoacrylic acid, 2-bromoacrylic acid, dimethyl allylmalonate, and allylmalonic acid was catalyzed by [{P boolean AND O}PdMe(L)] (L = C2H3N) (S.ACN), and the highest incorporation of 11.8% was observed for dimethyl allylmalonate (DMAM). The changes in the surface properties of the copolymers after incorporation of difunctional olefins were evaluated by measuring the water contact angle. Copolymer with highest (11.8% of DMAM) incorporation revealed a reduced water contact angle of 76 degrees. These findings demonstrate that 1,1-disubstituted difunctional olefins are amenable to polymerization, and incorporation of difunctional olefins In polyethylene backbone leads to the production of relatively hydrophilic polyethylene copolymers.1 aGaikwad, Shahaji, R.1 aDeshmukh, Satej, S.1 aKoshti, Vijay, S.1 aPoddar, Suparna1 aGonnade, Rajesh, G.1 aRajamohanan, Pattuparambil, R.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/reactivity-difunctional-polar-monomers-and-ethylene-copolymerization-comprehensive-account02509nas a2200241 4500008004100000245014200041210006900183260000800252300001400260490000700274520163100281100001701912700002401929700002401953700001601977700001701993700001902010700003502029700002202064700003002086700002402116856012702140 2017 eng d00aSecondary interactions arrest the hemiaminal intermediate to invert the modus operandi of schiff base reaction: a route to benzoxazinones0 aSecondary interactions arrest the hemiaminal intermediate to inv cAPR a4342-43510 v823 aDiscovered by Hugo Schiff, condensation between amine and aldehyde represents one of the most ubiquitous reactions in chemistry. This classical reaction is widely used to manufacture pharmaceuticals and fine chemicals. However, the rapid and reversible formation of Schiff base prohibits formation of alternative products, of which benzoxazinones are an important class. Therefore, manipulating the reactivity of two partners to invert the course of this reaction is an elusive target. Presented here is a synthetic strategy that regulates the sequence of Schiff base reaction via weak secondary interactions. Guided by the computational models, reaction between 2,3,4,5,6-pentafluoro-benzaldehyde with 2-amino-6methylbenzoic acid revealed quantitative (99%) formation of 5-methyl-2-(perfluoropheny01,2-dihydro-4H-benzo[d][1,3]oxazin-4-one (15). Electron donating and electron withdrawing ortho-substituents on 2-aminobenzoic acid resulted in the production of benzoxazinones 936. The mode of action was tracked using low temperature NMR, IN vis spectroscopy, and isotopic (O-18) labeling experiments. These spectroscopic mechanistic investigations revealed that the hemiaminal intermediate is arrested by the hydrogen-bonding motif to yield benzoxazinone. Thus, the mechanistic investigations and DFT calculations categorically rule out the possibility of in situ imine formation followed by ring-closing, but support instead hydrogen-bond assisted ring-closing to prodrugs. This unprecedented reaction represents an interesting and competitive alternative to metal catalyzed and classical methods of preparing benzoxazinone.1 aPatel, Ketan1 aDeshmukh, Satej, S.1 aBodkhe, Dnyaneshwar1 aMane, Manoj1 aVanka, Kumar1 aShinde, Dinesh1 aRajamohanan, Pattuparambil, R.1 aNandi, Shyamapada1 aVaidhyanathan, Ramanathan1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/secondary-interactions-arrest-hemiaminal-intermediate-invert-modus-operandi-schiff-base03179nas a2200169 4500008004100000245012700041210006900168260000800237300001600245490000700261520253100268100002202799700001702821700001902838700002402857856012802881 2017 eng d00a Self-assembly of P-chiral supramolecular phosphines on rhodium and direct evidence for Rh-catalyst-substrate interactions0 aSelfassembly of Pchiral supramolecular phosphines on rhodium and cOCT a13966-139730 v463 aSupramolecular phosphine-derived catalysts are known to provide high enantioselectivity in asymmetric transformations such as hydrogenation, but direct evidence unravelling the role of secondary interactions is largely missing. As a representative case study, the role of hydrogen bonding in asymmetric hydrogenation catalysed by p-chiral supramolecular phosphines is investigated. To establish the nature of hydrogen bonding in the self-assembled Rh-complex, NMR experiments were performed at different concentrations and temperatures. It was found that with increasing concentration of 1-(3-(phenyl(o-tolyl)phosphanyl) phenyl) urea ligand (L1), the NH and NH2 peaks shift downfield. This indicated the presence of intermolecular hydrogen bonding in L1. This observation was further supported by variable temperature NMR experiments wherein, with decreasing temperature, the NH and NH2 resonances of L1 shifted downfield. The downfield shift once again suggests the existence of intermolecular hydrogen bonding in L1. In contrast, the chemical shift of NH and NH2 signals did not significantly change with increasing concentration of the self-assembled Rh-complex (C1). This observation suggested the existence of intramolecular hydrogen bonding in the self-assembled complex. The concentration experiment was further corroborated by variable temperature NMR experiments. No change in the chemical shift of NH2 resonance could be detected with decreasing temperature, which corroborates the existence of intramolecular hydrogen bonding in C1. In a stoichiometric experiment, C1 was treated with hydrogenation substrate N-acetyldehydrophenylalanine (S2) and the proton NMR was recorded. The NH2 protons of the selfassembled Rh-complex were found to shift downfield, as compared to untreated parent C1. These observations indicated that there is a hydrogen bonding interaction between the Rh-complex and the substrate. To further attest this hypothesis, NH and NH2 groups were exchanged with ND and ND2 groups, respectively, and a self-assembled Rh-complex was prepared using the deuterated supramolecular phosphine ligand L1.D. When the deuterated Rh-complex (C1.D) was treated with substrate S2, the ND and ND2 resonances were found to shift downfield. Thus, the labelling experiment further authenticated the existence of catalyst-substrate interactions. The presence of this catalyst-substrate interaction could be one of the parameters that leads to high enantiomeric excess in the asymmetric hydrogenation reaction of S2.1 aKoshti, Vijay, S.1 aSen, Anirban1 aShinde, Dinesh1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/self-assembly-p-chiral-supramolecular-phosphines-rhodium-and-direct-evidence-rh-catalyst01562nas a2200157 4500008004100000245006700041210006300108260000800171490000600179520101500185100002601200700003501226700002201261700002401283856009701307 2017 eng d00aSynthesis of isohexide-di(ether-ene)s and ADMET polymerization0 aSynthesis of isohexidedietherenes and ADMET polymerization cJUN0 v53 aAs the fossil fuel reserves deplete and the greenhouse gases increase, the scientific community is challenged to provide sustainable solutions. Sugar-based isohexides can be modified to prepare a library of isohexide-diene monomers for polymerization. Such isohexide diene monomers can be subjected to Acyclic Diene Metathesis Polymerization to obtain green materials. Here we report a single step synthetic protocol to access a small family of isohexide-di(ether-ene)s and the corresponding polymers. The isohexide di(ether-ene)s 2a-2c could be isolated in good to excellent yields under optimized conditions. The resultant isohexide-di(ether-ene)s 2a-2c are potential versatile building blocks for pharmaceuticals and material science. The synthetic utility of 2a-2c was demonstrated by subjecting them to ADMET polymerization using Grubbs 1st and 2nd generation catalysts. The resultant viscous material was evaluated using 1H NMR and MALDI-ToF-MS, which suggests the formation of anticipated ADMET polymers1 aRajput, Bhausaheb, S.1 aLekshmy, Kalpakasseril, Girija1 aMenon, Shamal, K.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/synthesis-isohexide-diether-enes-and-admet-polymerization02077nas a2200181 4500008004100000245010200041210006900143260000800212300001400220490000800234520140600242100002401648700002501672700002201697700002101719700002401740856013101764 2017 eng d00aSynthesis of meta-substituted monodentate phosphinite ligands and implication in hydroformylation0 aSynthesis of metasubstituted monodentate phosphinite ligands and cAUG a1143-11520 v1293 aSynthesis of meta-substituted phosphinite ligands 3,3'-(methoxyphosphanediyl) bis(N, N-diethylaniline) (4a) and methoxybis(3-methoxyphenyl) phosphane (4b), in high yields, has been demonstrated. Typical phosphorus chemical shift between 110-120 ppm, appearance of methoxy protons and corresponding carbon, as well as ESI-MS spectra unambiguously confirmed the existence of phosphinite ligands 4a and 4b. To demonstrate the synthetic usefulness of 4a and 4b, these ligands were tested in the rhodium catalyzed hydroformylation of 1-octene. The diethylamine substituted ligand 4a was found to be highly active, whereas 4bwas less reactive but revealed slightly better regioselectivity of 62% under optimized conditions. Additionally, 4a and 4b were found to catalyze the hydroformylation of styrene, 1-undecenol and 1,1-disubstituted functional olefin, methyl methacrylate. Both the ligands displayed excellent conversion of styrene, and 4b revealed an excellent branch selectivity of 75%. Although 1-undecenol proved to be amenable to hydroformylation (85-90% conversion to aldehyde), both the ligands failed to discriminate between the linear and branched products. Substrate methyl methacrylate proved to be highly challenging and reduced conversion (between 33-42%) was observed under optimized conditions. Ligand 4a was found to be highly selective towards linear aldehyde (81% linear selectivity).1 aDeshmukh, Satej, S.1 aGaikwad, Shahaji, R.1 aPandey, Swechchha1 aMali, Pramod, S.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/synthesis-meta-substituted-monodentate-phosphinite-ligands-and-implication-hydroformylation01673nas a2200109 4500008004100000245006400041210006400105260000800169520126100177100002401438856010101462 2017 eng d00aZiegler–Natta polymerization and the remaining challenges0 aZiegler–Natta polymerization and the remaining challenges cNOV3 aPolymers have become indispensable in the 21st century, and today we cannot imagine life without them. However, till around the beginning of the last century, the science of polymers was considered a very primitive discipline, and majority of the scientific community did not believe that polymers even existed. Hermann Staudinger, among others, fought a long battle to convince the scientific community that polymers are real and that they are long chain molecular entities. Building on this rational bedrock of polymer science, Prof. Karl Ziegler laid the foundation of ethylene polymerization. As outlined by Dr. Sivaram in his articles on Ziegler and Natta, careful observations and systematic analyses of serendipitous results enabled Ziegler to deveop the enormously significant ‘Mulheim atmospheric polyethylene process’. A decade later, ¨ Cossee and Arlman revealed the mechanism of this polymerization reaction, which is called ‘insertion polymerization’. Insertion polymerization is popularly known as the ‘Ziegler– Natta polymerization’, in recognition of its founding fathers. Today, the world produces about 180 million tons of polyolefins annually, and polyethylene or polythene has become a household name.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/ziegler%E2%80%93natta-polymerization-and-remaining-challenges01794nas a2200157 4500008004100000022001500041245009300056210006900149260000800218300001400226520120700240100002201447700002301469700002401492856012001516 2018 eng d a 1434-193X00aAccelerated and enantioselective synthesis of a library of p-stereogenic urea phosphines0 aAccelerated and enantioselective synthesis of a library of pster cDEC a6768-67793 aChiral phosphorus ligands play a central role in majority of the asymmetric transformations. However, access to chiral phosphorus ligands is limited due to their challenging synthesis. Reported here is a highly efficient and accelerated catalytic asymmetric synthesis of P-stereogenic urea containing phosphines leading to a small library of 18 chiral phosphorus compounds. Characteristic two doublets in a P-31 NMR spectrum, spectroscopic and analytical evidences authenticated the formation of [Pd-{(S,S) Me-FerroLANE}(m-phenylurea)(I)] complex. Indeed, [Pd-{(S,S) Me-FerroLANE}(m-phenylurea)(I)] was found to catalyze the C-P coupling reaction and quantitative conversion was observed within 18 hours. Under optimized conditions, iodophenyl urea's (2a-2j) were treated with secondary phosphines (1a-1c) in presence of [Pd-{(S,S) Me-FerroLANE}(m-phenylurea)(I)] to obtain P-stereogenic urea phosphines 5a-5r. The identity of these urea derived phosphines was unambiguously ascertained using a combination of spectroscopic and analytical methods. The catalyst tolerated various functional groups and yielded corresponding urea containing phosphines with an enantiomeric excess in the range of 15-62 %.1 aKoshti, Vijay, S.1 aGote, Ravindra, P.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/accelerated-and-enantioselective-synthesis-library-p-stereogenic-urea-phosphines02237nas a2200181 4500008004100000245009800041210006900139260000800208300001400216490000700230520157300237100002601810700001501836700002201851700003101873700002401904856012701928 2018 eng d00aCross-metathesis of biorenewable dioxalates and diols to film-forming degradable polyoxalates0 aCrossmetathesis of biorenewable dioxalates and diols to filmform cJUL a1584-15920 v563 aStarting from commonly available sugar derivatives, a single step protocol to access a small family of isohexide-dioxalates (2a-c) has been established. The synthetic competence of 2a-c has been demonstrated by subjecting them to condensation polymerization. Quite surprisingly, the proton NMR of poly(isomannide-co-hexane)oxalate revealed a 1:2 ratio between isomannide-dioxalate (2a) and 1,6-hexanediol (3a) in the polymer backbone. This intriguing reactivity was found to be an outcome of a cross metathesis reaction between 2a and 3a. The cross metathesis products 3a[2-(2-methoxyacetoxy)ethyl 2-(2-hydroxyethoxy)-2-(3-oxydanylidene)acetate] and 2a(3R,6R)-6-hydroxyhexahydrofuro[3,2-b]-furan-3-yl methyl oxalate were isolated in a control experiment. Based on direct and indirect evidence, and control experiments, an alternative polymerization mechanism is proposed. Polymerization conditions were optimized to obtain polyoxalates P1(2a-3a)-P9(2c-3c) with molecular weights in the range of 14,000-68,000 g/mol, and narrow polydispersities. The identity of the polyoxalates was unambiguously established using 1-2D NMR spectroscopy, MALDI-ToF-MS, and GPC measurements. The practical implication of these polymers is demonstrated by preparing transparent, mechanically robust films. The environmental footprint of the selected polyoxalates was investigated by subjecting them to solution and solid-state degradation. The polyoxalates were found to be amenable to degradation. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1584-15921 aRajput, Bhausaheb, S.1 aRam, Farsa1 aMenon, Shamal, K.1 aShanmuganathan, Kadhiravan1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/cross-metathesis-biorenewable-dioxalates-and-diols-film-forming-degradable-polyoxalates01881nas a2200157 4500008004100000022001500041245006200056210006200118260000800180300001400188490000700202520137200209100002101581700002401602856009701626 2018 eng d a 1861-472800aHydrogen bonding assissted supramolecular metal catalysis0 aHydrogen bonding assissted supramolecular metal catalysis cDEC a3623-36460 v133 aThe process of catalyst screening and discovery still largely relies on traditional ligand-design approaches, which suffer from complex synthetic requirements and offer limited structural diversity. On the contrary, supramolecular chemistry offers the potential to harness multiple weak secondary interactions to deliver self-assembled catalysts with diverse structures or to orient substrates to achieve enzyme-like activity and selectivity. Herein, the application of hydrogen-bonding (H-bonding) interactions as a construction element and directing group in "supramolecular transition-metal catalysis" is critically reviewed and the current state-of-the-art in the field is presented. H-bonding interactions empower structurally simple ligands to deliver complex self-assembled catalysts, which have been found to catalyze a gamut of organic transformations, including hydroformylation, hydrogenation, and allylation reactions. As we will discuss, on many occasions, these supramolecular catalysts outperform their analogous covalently linked catalytic systems. The potential of H-bonding interactions as directing groups has recently been recognized by the scientific community and this Focus Review presents the role of hydrogen-bonding interactions in directing substrates to obtain excellent selectivities and activities in a range of catalytic transformations1 aMote, Nilesh, R.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/hydrogen-bonding-assissted-supramolecular-metal-catalysis01877nas a2200157 4500008004100000022001500041245006100056210005900117260000800176300001400184490000700198520137300205100002101578700002401599856009601623 2018 eng d a1861-4728 00aHydrogen-bonding-assisted supramolecular metal catalysis0 aHydrogenbondingassisted supramolecular metal catalysis cDEC a3623-36460 v133 aThe process of catalyst screening and discovery still largely relies on traditional ligand-design approaches, which suffer from complex synthetic requirements and offer limited structural diversity. On the contrary, supramolecular chemistry offers the potential to harness multiple weak secondary interactions to deliver self-assembled catalysts with diverse structures or to orient substrates to achieve enzyme-like activity and selectivity. Herein, the application of hydrogen-bonding (H-bonding) interactions as a construction element and directing group in "supramolecular transition-metal catalysis" is critically reviewed and the current state-of-the-art in the field is presented. H-bonding interactions empower structurally simple ligands to deliver complex self-assembled catalysts, which have been found to catalyze a gamut of organic transformations, including hydroformylation, hydrogenation, and allylation reactions. As we will discuss, on many occasions, these supramolecular catalysts outperform their analogous covalently linked catalytic systems. The potential of H-bonding interactions as directing groups has recently been recognized by the scientific community and this Focus Review presents the role of hydrogen-bonding interactions in directing substrates to obtain excellent selectivities and activities in a range of catalytic transformations.1 aMote, Nilesh, R.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/hydrogen-bonding-assisted-supramolecular-metal-catalysis02690nas a2200229 4500008004100000022001400041245011000055210006900165260000900234300001400243490000800257520190300265100002202168700001502190700002302205700001702228700002402245700002402269700001802293700002402311856012502335 2018 eng d a0002-786300aIron Catalyzed Hydroformylation of Alkenes under Mild Conditions: Evidence of an Fe(II) Catalyzed Process0 aIron Catalyzed Hydroformylation of Alkenes under Mild Conditions cMAR  a4430-44390 v1403 a

Earth abundant, first row transition metals offer a cheap and sustainable alternative to the rare and precious metals. However, utilization of first row metals in catalysis requires harsh reaction conditions, suffers from limited activity, and fails to tolerate functional groups. Reported here is a highly efficient iron catalyzed hydroformylation of alkenes under mild conditions. This protocol operates at 10-30 bar syngas pressure below 100 degrees C, utilizes readily available ligands, and applies to an array of olefins. Thus, the iron precursor [HFe(CO)(4)](-)[Ph3PNPPh3](+) (1) in the presence of triphenyl phosphine catalyzes the hydroformylation of 1-hexene (S2), 1-octene (S1), 1-decene (S3), 1-dodecene (S4), 1-octadecene (S5), trimethoxy(vinyl)silane (S6), trimethyl(vinyl)silane (S7), cardanol (S8), 2,3-dihydrofuran (S9), allyl malonic acid (S10), styrene (S11), 4-methylstyrene (S12), 4-iBu-styrene (S13), 4-tBu-styrene (S14), 4-methoxy styrene (S15), 4-acetoxy styrene (S16), 4-bromo styrene (S17), 4-chloro styrene (S18), 4-vinylbenzonitrile (S19), 4-vinylbenzoic acid (S20), and allyl benzene (S21) to corresponding aldehydes in good to excellent yields. Both electron donating and electron withdrawing substituents could be tolerated and excellent conversions were obtained for S11-S20. Remarkably, the addition of 1 mol % acetic acid promotes the reaction to completion within 16-24 h. Detailed mechanistic investigations revealed in situ formation of an iron-dihydride complex [H2Fe(CO)(2)(PPh3)(2)] (A) as an active catalytic species. This finding was further supported by cyclic voltammetry investigations and intermediacy of an Fe(0)-Fe(II) species was established. Combined experimental and computational investigations support the existence of an iron-dihydride as the catalyst resting state, which then follows a Fe(II) based catalytic cycle to produce aldehyde.

1 aPandey, Swechchha1 aRaj, Vipin1 aShinde, Dinesh, R.1 aVanka, Kumar1 aKashyap, Varchaswal1 aKurungot, Sreekumar1 aVinod, C., P.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/iron-catalyzed-hydroformylation-alkenes-under-mild-conditions-evidence-feii-catalyzed02653nas a2200217 4500008004100000022001400041245012000055210006900175260000900244300001400253490000700267520188500274100002302159700001702182700001702199700002702216700001802243700002102261700002402282856012902306 2018 eng d a0024-929700aJudicious reduction of supported Ti catalyst enables access to disentangled ultrahigh molecular weight polyethylene0 aJudicious reduction of supported Ti catalyst enables access to d cJUN  a4541-45520 v513 a

Heterogeneous Ziegler-Natta and homogeneous metallocene catalysts are known to produce ultrahigh molecular weight polyethylene (UHMWPE) in the entangled state. On the other hand, only (two) homogeneous single-site catalysts are reported to yield disentangled UHMWPE (dis-UHMWPE). This disparity between the two types of catalysts and the two states of polyethylene can be bridged if a heterogeneous single-site catalyst that can yield dis-UHMWPE is made accessible. Here, one-pot two-step synthesis of a MgCl2 supported [Ti(OEt)(4)] derived catalyst 1 with a two-stage activation strategy is reported to produce dis-UHMWPE. Second activation of catalyst 1 was performed by adding excess modified methylaluminoxane (MMAO12), and XPS analysis indicated that the catalyst existed in only Ti(III) state at [A1]/[Ti] ratio of 600. Catalyst 1 after second activation with MMAO12 was found to be highly active in ethylene polymerization and produced dis-UHMWPE. Polymerization conditions were tailored to obtain molecular weight (M-w) as high as 13 million g/mol PE. To the best of our knowledge, this is the first time a heterogeneous catalyst (catalyst 1) that displays pseudosingle site nature is able to produce dis-UHMWPE. The thus-prepared nascent polyethylene revealed a melting temperature of 141-144 degrees C, which is a characteristic melting transition for a dis-UHMVVPE. The disentangled state of the nascent PE and its M-w and MVVD were further authenticated by rheological investigations. Isothermal time, sweep oscillatory experiments in linear viscoelastic limit revealed a rapid rise in elastic modulus followed by equilibration to plateau modulus, which are characteristic features of the disentangled state. Thus, a pseudo-singlesite heterogeneous catalyst has been accessed, which upon second activation with excess MMAO12 led to the production of dis-UHMWPE.

1 aGote, Ravindra, P.1 aMandal, Dipa1 aPatel, Ketan1 aChaudhuri, Krishnaroop1 aVinod, C., P.1 aLele, Ashish, K.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/judicious-reduction-supported-ti-catalyst-enables-access-disentangled-ultrahigh-molecular00611nas a2200157 4500008004100000245008600041210006900127260000800196300002800204490000800232100002400240700003200264700002100296700002500317856011100342 2018 eng d00aModern trends in inorganic chemistry: celebration of inorganic chemistry in India0 aModern trends in inorganic chemistry celebration of inorganic ch cJUL aArticle Number: UNSP 750 v1301 aChikkali, Samir, H.1 aAnand, Venkataramanarao, G.1 aSrinivas, Darbha1 aKumbhar, Avinash, S. uhttps://library.ncl.res.in/content/modern-trends-inorganic-chemistry-celebration-inorganic-chemistry-india02237nas a2200205 4500008004100000022001400041245011100055210006900166260000800235300001400243490000600257520151000263100002401773700002501797700002101822700001401843700002401857700002401881856012601905 2019 eng d a2470-134300aNeutral imino-methyl benzenesulfonate-ligated Pd(II) complexes and implications in ethylene polymerization0 aNeutral iminomethyl benzenesulfonateligated PdII complexes and i cMAY a9502-95110 v43 a

A reaction between sodium 2-formylbenzenesulfonate and aniline revealed the near-quantitative (91%) formation of sodium-2-((phenylimino)methyl)benzenesulfonate L1. The identity of L1 was unambiguously ascertained using spectroscopic and analytical methods. The scope of this methodology was widened and various electron-donating amines were treated with sodium 2-formylbenzenesulfonate, and a small library of 6 imine ligands L2-L6 was generated. When L2 was treated with [(COD)PdMeCI], instead of the anticipated [L2PdMe(DMSO)] complex, the formation of [(DMSO)(2)Pd2Cl2Me2] Pd Dim was observed. Nevertheless, the desired imino-methyl benzenesulfonate-ligated palladium complex [L2PdMe(Lu)] C1 was obtained by in situ abstraction of chloride and addition of bulky 2,6-lutidine as the donor group. The observation of characteristic Pd-Me protons at 0.06 ppm and the corresponding carbon at -8.1 ppm indicated the formation of C1. These 1D NMR observations were corroborated by 2D C-H correlation spectra and mass analysis, and the existence of C1 was unambiguously ascertained. Along the same lines, L4 and L5 were treated with a palladium precursor to produce [L4/SPdMe(Lu)]-type complexes C2-C3 in 55-84% yield, and their identity was established by using a combination of spectroscopic tools, analytical methods, and single-crystal X-ray diffraction. The synthetic utility of C1-C3 has been demonstrated by utilizing these complexes in the insertion polymerization of ethylene to polyethylene.

1 aDeshmukh, Satej, S.1 aGaikwad, Shahaji, R.1 aMote, Nilesh, R.1 aManod, M.1 aGonnade, Rajesh, G.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/neutral-imino-methyl-benzenesulfonate-ligated-pdii-complexes-and-implications-ethylene01217nas a2200121 4500008004100000245006700041210006700108260000800175520076700183100002200950700002400972856009900996 2019 eng d00aNoncovalent interactions in hydrogenation and hydroformylation0 aNoncovalent interactions in hydrogenation and hydroformylation bRSC3 aThis chapter summarizes the fundamentals of hydrogenation and hydroformylation reactions. An overview of state-of-the-art developments is presented to set the context. Subsequently, the significance of noncovalent interactions in these reactions is discussed in detail. Hydrogen bonding has been one of the leading noncovalent interactions that has been very frequently used in catalysis, including hydrogenation and hydroformylation reactions. Recent examples from the literature are presented to illustrate the role of hydrogen bonding in hydrogenation and hydroformylation. The impact of hydrogen bonding on catalyst development through self-assembly and the role of hydrogen bonding in directing a substrate to achieve high enantiomeric excess are discussed.1 aKoshti, Vijay, S.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/noncovalent-interactions-hydrogenation-and-hydroformylation01241nas a2200289 4500008004100000022001400041245005300055210005300108260000800161300001200169490000600181520040000187653002900587653001400616653002200630653001200652653001600664100002000680700001700700700002700717700002400744700002500768700002500793700002400818700002400842856008500866 2020 eng d a2193-580700aHighly enantioselective synthesis of sitagliptin0 aHighly enantioselective synthesis of sitagliptin cFEB a189-1910 v93 a

A highly enantioselective synthesis of sitagliptin, a potent DPP-4 inhibitor, is reported. Explicitly identified chiral FerroLANE ligands in the presence of rhodium catalyze the asymmetric hydrogenation of an enamine to yield sitagliptin with excellent enantioselectivity (98% ee). The process was scaled up to 5 g and the final product was isolated as a phosphate salt with >99% ee.

10aasymmetric hydrogenation10acatalysis10aFerroLANE ligands10aRhodium10asitagliptin1 aKhopade, Kishor1 aSen, Anirban1 aBirajdar, Rajkumar, S.1 aPaulbudhe, Uday, P.1 aKavale, Dattatry, S.1 aShinde, Prashant, S.1 aMhaske, Santosh, B.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/highly-enantioselective-synthesis-sitagliptin02037nas a2200289 4500008004100000022001400041245013000055210006900185260000800254300001400262490000700276520106100283653002601344653003101370653001201401653001401413653001701427100002501444700001701469700002401486700002101510700002701531700002401558700002101582700002401603856012001627 2020 eng d a2192-650600aPalladium-catalyzed insertion of ethylene and 1,1-disubstituted difunctional olefins: an experimental and computational study0 aPalladiumcatalyzed insertion of ethylene and 11disubstituted dif cJUN a1200-12090 v853 a

Insertion or coordination copolymerization of ethylene with di-substituted olefins is challenging and the choice of di-substituted mono-functional olefin versus di-substituted di-functional olefin (DDO) appears to be decisive. Here we show that DDO-inserted species are amenable to ethylene insertion and polymerization. DDOs such as 2-acetamidoacrylic acid (AAA), methyl 2-acetamidoacrylate (MAAA), and ethyl 2-cyanoacrylate (ECA) were treated with palladium complex [{P perpendicular to O}PdMe(L)] (P perpendicular to O=kappa(2)-P,O-Ar2PC6H4SO2O with Ar=2-MeOC6H4; L=C2H6OS) and the existence of respective insertion intermediates in moderate yield (up to 37 %) was established. These intermediates were exposed to ethylene and corresponding ethylene-inserted products were isolated and characterized. A careful comparison with three model compounds confirmed ethylene insertion and polymerization. Thus, the combined experimental and computational investigations show that DDO-inserted species can undergo ethylene insertion and polymerization.

10aHomogeneous catalysis10ainsertion copolymerization10aOlefins10aPalladium10aPolyethylene1 aGaikwad, Shahaji, R.1 aPatel, Ketan1 aDeshmukh, Satej, S.1 aMote, Nilesh, R.1 aBirajdar, Rajkumar, S.1 aPandole, Satish, P.1 aChugh, Jeetender1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/palladium-catalyzed-insertion-ethylene-and-11-disubstituted-difunctional-olefins02236nas a2200253 4500008004100000022001400041245008000055210006900135260000900204300001200213490000700225520142200232653001001654653002201664653002901686653001701715653001701732100002401749700002501773700002401798700002401822700002401846856011201870 2020 eng d a1861-472800aPd-iminocarboxylate complexes and their behavior in ethylene polymerization0 aPdiminocarboxylate complexes and their behavior in ethylene poly cFEB  a398-4050 v153 a

Designing co-catalyst-free late transition metal complexes for ethylene polymerization is a challenging task at the interface of organometallic and polymer chemistry. Herein, a set of new, co-catalyst-free, single-component catalytic systems for ethylene polymerization have been unraveled. Treatment of anthranilic acid with various aldehydes produced four iminocarboxylate ligands (L1-L4) in very good to excellent yield (75-92 %). The existence of 2-((2-methoxybenzylidene)amino) benzoic acid (L1) has been unambiguously demonstrated using NMR spectroscopy, MS and single-crystal X-ray diffraction. A neutral Pd-iminocarboxylate complex [{N O}PdMe(L1)] (N O=kappa(2)-N,O-ArCHNC6H4CO2 with Ar=2-MeOC6H4) C1 was prepared by treating stoichiometric amount of L1.Na with palladium precursor. The identity of C1 was confirmed by 1-2D NMR spectroscopy and single-crystal X-ray diffraction studies. Along the same lines, palladium complexes C2-C4 were prepared from ligands L2-L4 respectively. In-situ high-pressure NMR investigations revealed that these Pd complexes are amenable to ethylene insertion and undergo facile beta-H elimination to produce propylene. These palladium complexes were then evaluated in ethylene polymerization reaction and various reaction parameters were screened. When C1-C4 were exposed to ethylene pressures of 10-50 bar, formation of low-molecular-weight polyethylene was observed.

10aimine10aImine-carboxylate10aInsertion polymerization10aPd complexes10aPolyethylene1 aDeshmukh, Satej, S.1 aGaikwad, Shahaji, R.1 aGonnade, Rajesh, G.1 aPandole, Satish, P.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/pd-iminocarboxylate-complexes-and-their-behavior-ethylene-polymerization02148nas a2200265 4500008004100000022001400041245010600055210006900161260000900230300001100239490000800250520122800258653002901486653003101515653002401546653001701570653001001587100002601597700002201623700002401645700002401669700003301693700002401726856013201750 2020 eng d a0014-305700aRenewing polyethylene: insertion copolymerization of sugar derived hydrophilic monomers with ethylene0 aRenewing polyethylene insertion copolymerization of sugar derive cJUL  a1097750 v1343 a

Although highly desirable, insertion copolymerization of renewable resource derived functional olefins with ethylene has been rarely investigated. Herein, we report insertion copolymerization of challenging sugar derived isohexide mono-enes with ethylene in the presence of Pd-phosphinesulfonate acetonitrile catalyst (C1). Thus, copolymerization of ethylene with isomannide mono-ene (2a), isosorbide mono-ene (2b'), isoidide mono-ene (2c) and methacryl-2,3,4,6-tetra-O-acetyl-D glucopyranoside (2d) afforded corresponding functionalized polyethylene (P2a-1 to P2d-1). High temperature proton NMR investigations revealed enchainment of 2a-2c in polyethylene backbone and the highest incorporation of 1.45% was observed for 2c. The high temperature proton NMR results were further corroborated by solid state C-13 NMR and IR spectroscopy. Gel permeation chromatography analysis displayed weight average molecular weight in the range of 13.0-27.2 x 10(3) g/mol. The thus prepared copolymers revealed melting temperature in the range of 117-126 degrees C. Relatively reduced melting temperature compared to neat polyethylene may suggest an irregular arrangement of pendant functional group on polyethylene main chain.

10aHydrophilic polyethylene10ainsertion copolymerization10aIsohexide mono-enes10aPolyethylene10aSugar1 aRajput, Bhausaheb, S.1 aPawal, Sandip, B.1 aBodkhe, Dnyaneshwar1 aRao, Nagamalleswara1 aSainath, Annadanam, V. Sesha1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/renewing-polyethylene-insertion-copolymerization-sugar-derived-hydrophilic-monomers-ethylene02005nas a2200229 4500008004100000022001400041245010700055210006900162260000800231300001100239490000800250520119300258653002501451653002401476653002101500653002201521653004101543100001701584700002401601700002501625856012501650 2020 eng d a0079-670000aUltrahigh molecular weight polyethylene: catalysis, structure, properties, processing and applications0 aUltrahigh molecular weight polyethylene catalysis structure prop cOCT a1012900 v1093 a

Ultrahigh molecular weight polyethylene (UHMWPE) belongs to an emerging class of high-performance specialty polymers with a unique set of properties and applications. The field has witnessed many scientific and technological advances in recent years. However, synthesis of UHMWPE is not a trivial exercise and presents several challenges. This review addresses these fundamental challenges and provides an overview of recent developments in the field of UHMWPE. The nature of catalysts, reaction conditions that favor its formation, their physical properties, methods of processing them into products, and their applications are discussed. Recent developments in formation of UHMWPE in a disentangled state by use of appropriate catalysts and reaction conditions are also discussed. This has elicited considerable interest as a means of enabling melt processing of UHMWPE. This review provides a comprehensive source of information and understanding of the multifaceted aspects of UHMWPE with specific reference to chemistry, catalysis, processes for manufacturing, and an analysis of catalyst structure-polymer property relationships. (C) 2020 Elsevier B.V. All rights reserved.

10aCatalysts for UHMWPE10aDisentangled UHMWPE10aEntangled UHMWPE10apolyethylene (PE)10aUltrahigh molecular weight (UHMW) PE1 aPatel, Ketan1 aChikkali, Samir, H.1 aSivaram, Swaminathan uhttps://library.ncl.res.in/content/ultrahigh-molecular-weight-polyethylene-catalysis-structure-properties-processing-and02158nas a2200157 4500008004100000022001400041245011300055210006900168260000900237300001400246490000700260520156200267100001701829700002401846856013001870 2021 eng d a1477-052000aC (1)-Symmetric diphosphorus ligands in metal-catalyzed asymmetric hydrogenation to prepare chiral compounds0 aC 1Symmetric diphosphorus ligands in metalcatalyzed asymmetric h cNOV  a9095-91370 v193 aAsymmetric hydrogenation has remained an important and challenging research area in industry as well as academia due to its high atom economy and ability to induce chirality. Among several types of ligands, chiral bidentate phosphine ligands have played a pivotal role in developing asymmetric hydrogenation. Although C-2-symmetric chiral bidentate phosphine ligands have dominated the field, it has been found that several C-1-symmetric ligands are equally effective and, in many cases, have outperformed their C-2-symmetric counterparts. This review evaluates the possibility of the use of C-1-symmetric diphosphorus ligands in asymmetric hydrogenation to produce chiral compounds. The recent strategies and advances in the application of C-1-symmetric diphosphorus ligands in the metal-catalyzed asymmetric hydrogenation of a variety of C=C bonds have been summarized. The potential of diphosphorus ligands in asymmetric hydrogenation to produce pharmaceutical intermediates, bioactive molecules, drug molecules, agrochemicals, and fragrances is discussed. Although asymmetric hydrogenation appears to be a problem that has been resolved, a deep dive into the recent literature reveals that there are several challenges that are yet to be addressed. The current asymmetric hydrogenation methods mostly employ precious metals, which are depleting at a fast pace. Therefore, scientific interventions to perform asymmetric hydrogenation using base metals or earth-abundant metals that can compete with established precious metals hold significant potential.1 aSen, Anirban1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/c-1-symmetric-diphosphorus-ligands-metal-catalyzed-asymmetric-hydrogenation-prepare-chiral02478nas a2200193 4500008004100000022001400041245012500055210006900180260000900249300001400258490000700272520177700279100002102056700002502077700000502102700002402107700002402131856012902155 2021 eng d a1477-922600aControlled di-lithiation enabled synthesis of phosphine-sulfonamide ligands and implications in ethylene oligomerization0 aControlled dilithiation enabled synthesis of phosphinesulfonamid cMAR  a3717-37230 v503 a

Catalyst design for ethylene oligomerization has attracted significant interest. Herein, we report the synthesis of phosphine-sulfonamide-derived palladium complexes and examine their performance in ethylene oligomerization. Arresting a dilithiation intermediate of N-(2-bromophenyl)-4-methylbenzenesulfonamide (1) at -84 degrees C selectively produced N-(2-(bis(2-methoxyphenyl)phosphanyl)phenyl)-4-methylbenzenesulfonamide (L1A). However, the same reaction at -41 degrees C delivered a different ligand; 2-(bis(2-methoxyphenyl)phosphanyl)-4-methyl-N-phenylbenzenesulfonamide (L2A). The generality of our strategy has been demonstrated by preparing N-(2-(diphenylphosphanyl)phenyl)-4-methylbenzenesulfonamide (L1B) and 2-(diphenylphosphanyl)-4-methyl-N-phenylbenzenesulfonamide (L2B). Subsequently, L1A and L1B were treated with a palladium precursor to yield 5-membered complexes C1 and C2, respectively. In contrast, L2A upon treatment with palladium produced a 6-membered metal complex C3. Thus, a small library of 7 palladium complexes (C1-C7) were synthesized by varying the donor moiety (pyridine, DMSO, and acetonitrile). The identity of palladium complexes was unambiguously ascertained using a combination of spectroscopic and analytical methods, including single-crystal X-ray diffraction. The performance of the complexes C1-C7 was investigated in ethylene oligomerization and almost all of them were found to be active. The resultant ethylene oligomers were characterized using H-1 and C-13 NMR, MALDI-ToF-MS, and GPC. Detailed screening of reaction parameters revealed 100 degrees C and 40 bars ethylene to be optimal conditions. Complex C5 outperformed other complexes and produced ethylene oligomers with a molecular weight of 1000-1900 g mol(-1).

1 aMote, Nilesh, R.1 aGaikwad, Shahaji, R.1 a1 aGonnade, Rajesh, G.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/controlled-di-lithiation-enabled-synthesis-phosphine-sulfonamide-ligands-and-implications03064nas a2200229 4500008004100000022001400041245006500055210006300120260000900183300001100192490000800203520233200211653001302543653002802556653002702584653002902611653003102640653001702671100002702688700002402715856009502739 2021 eng d a0014-305700aInsertion copolymerization of functional olefins: Quo Vadis?0 aInsertion copolymerization of functional olefins Quo Vadis cJAN  a1101830 v1433 a

Functional polyethylene is a specialty polymer with unique set of properties and caters to a niche market. Currently, it is manufactured using high-pressure, high-temperature radical polymerization, or post-reactor (indirect) modification methods. Insertion copolymerization of functional olefins with ethylene provides a low pressure, direct route to prepare functional polyethylenes. However, insertion copolymerization of functional olefins with ethylene poses several impediments and requires special considerations. This review presents the current strategies, examines the progress, and attempts to gauge the commercial potential of direct synthesis of functional polyethylene. The performance of late transition metal catalysts derived from a-diimine, imine-phenolate, phosphine-sulfonate, bis-phosphine-mono-oxide, carbene-phenolate, phosphine-phenolate and their derivatives in the insertion copolymerization of functional olefins with ethylene is evaluated. While catalyst designing is crucial, incorporation of polar olefins that can serve an additional purpose is equally important. Therefore, we have organized the review in the following sections, polar alkenes with- acrylates, acrylic acids, acetates, nitriles, ethers, halides, two functional groups, cross-linking groups, dynamic interactions/self-healing properties, additional function/purpose, renewable functional olefins, and examine the progress. Among these, acrylates have been most intensively investigated and have been successfully incorporated in the polyethylene main-chain. Ethylene, methyl acrylate copolymers prepared by direct copolymerization reveal comparable melting temperature to that of LLDPE (at similar co-monomer content) and unfold the commercial potential of these materials. Recent developments on the insertion copolymerization of renewable functional olefins and di-functional olefins have elicited significant interest. This strategy is being viewed as a means of reducing environmental impact and enabling high functional group density at the same extent of incorporation. The overview thus offers a succinct account of insertion copolymerization of functional olefins, sheds light on the copolymer microstructure/material properties, and initiates a discussion on the commercial potential of functional polyethylene.

10aCatalyst10aFunctional polyethylene10afunctional polyolefins10aHydrophilic polyethylene10ainsertion copolymerization10aPolyethylene1 aBirajdar, Rajkumar, S.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/insertion-copolymerization-functional-olefins-quo-vadis01722nas a2200241 4500008004100000022001400041245011000055210006900165260000800234300000800242490000800250520087600258653002501134653002001159653001701179653002801196653002701224100002501251700002701276700002101303700002401324856013201348 2021 eng d a0974-362600aNi-catalyzed highly enantioselective synthesis of sulfur protected P-stereogenic supramolecular phosphine0 aNicatalyzed highly enantioselective synthesis of sulfur protecte cDEC a1190 v1333 aAs phosphines readily invert, the synthesis of P-chiral phosphines is a challenging task and has been rarely investigated. We report the synthesis of a nickel complex [Ni-((S,S)Me-FerroLANE)(phenyl)(I)] (Ni-Cat.1) and its performance in a P-C coupling reaction to generate P-chiral phosphine. The Ni-Cat.1 was synthesized by mixing ligand (S,S) Me-FerroLANE with the metal precursor [(diphenylphosphanyl)nickel(phenyl)(I)] in good yield. Ni-Cat.1 was characterized using different spectroscopic and analytical techniques. Treatment of racemic methyl(phenyl)phosphine (1) with 1-(3-iodophenyl)urea (2) produced the corresponding P-chiral supramolecular phosphine (3). Optimization of reaction parameters produced sulfur protected phosphine N-(3-(methyl(phenyl)phosphorothioyl)phenyl)formamide (3') with excellent enantiomeric excess (99% ee) and moderate conversion (51%).10aAsymmetric synthesis10aNickel catalyst10aP-C coupling10aP-Stereogenic phosphine10asupramolecular ligands1 aKoshti(S), Vijay, S.1 aChandanshive, Amol, C.1 aMote, Nilesh, R.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/ni-catalyzed-highly-enantioselective-synthesis-sulfur-protected-p-stereogenic-supramolecular01819nas a2200217 4500008004100000022001400041245008100055210006900136260000800205520109100213653002601304653002101330653001801351653001201369653002301381100001901404700001701423700002701440700002401467856011001491 2021 eng d a1527-899900aPhosphorus ligands in hydroformylation and hydrogenation: a personal account0 aPhosphorus ligands in hydroformylation and hydrogenation a perso cMAR3 a

Metal-catalyzed hydroformylation and hydrogenation heavily rely on ligands, among which phosphorous ligands play a pivotal role. This personal account presents a selection of three distinct classes of phosphorous ligands, namely, monodentate meta-substituted phosphinites, bis-phosphites, and P-chiral supramolecular phosphines, developed in our group. The synthesis of these ligands, isolation, characterization, and their performance in transition metal-catalyzed hydroformylation, isomerizing hydroformylation, and asymmetric hydrogenation of olefins is summarized. The state of the art development in iron-catalyzed hydroformylation of alkenes and our contributions to the field is discussed. Use of phosphines enabled iron-catalyzed hydroformylation of alkenes under mild conditions. Thus, this account demonstrates the central role of phosphorus ligands in industrially relevant transformations such as hydrogenation and hydroformylation. The seemingly matured field of ligand discovery still holds significant potential and will steer the field of homogeneous catalysis.

10aHomogeneous catalysis10aHydroformylation10aHydrogenation10aOlefins10aPhosphorus ligands1 aTewari, Tanuja1 aKumar, Rohit1 aChandanshive, Amol, C.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/phosphorus-ligands-hydroformylation-and-hydrogenation-personal-account01736nas a2200169 4500008004100000022001400041245008100055210006900136260000800205300001400213490000700227520114900234100002201383700002601405700002401431856011101455 2021 eng d a1463-926200aRefining plant oils and sugars to platform chemicals, monomers, and polymers0 aRefining plant oils and sugars to platform chemicals monomers an cMAY a4255-42950 v233 a

As fossil resources continue to dwindle and environmental concerns are magnified, finding sustainable alternatives is the only way to mitigate resource availability and derisk the planet. The principles of Green Chemistry may provide guidance in this case, and renewable resources can be converted into useful platform chemicals, monomers, and polymers. This critical review examines the possibility of utilizing renewable plant oils and sugars to produce feedstock chemicals, monomers, and polymers. Among the seven isomerizing functionalization reactions of plant oils, isomerizing alkoxycarbonylation displays the highest terminal selectivity. Despite the low reactivity of sugar-derived isohexides, new strategies have been deployed to convert isohexides into difunctional monomers and polymers. The commercialization of isohexides and a few polymers derived from these building blocks has just commenced. Thus, challenges associated with isomerizing functionalization of plant oils and the use of sugar-derived isohexides in chemical syntheses have been summarized, and the potential of these renewable resources has been evaluated.

1 aPandey, Swechchha1 aRajput, Bhausaheb, S.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/refining-plant-oils-and-sugars-platform-chemicals-monomers-and-polymers01991nas a2200217 4500008004100000022001400041245006100055210006100116260000800177300001100185490000800196520135900204653001401563653001201577653001401589653002101603653002301624100001701647700002401664856008501688 2022 eng d a0022-328X00aHydroformylation of olefins by metals other than rhodium0 aHydroformylation of olefins by metals other than rhodium cFEB a1222310 v9603 aMetal catalyzed hydroformylation of alkenes is an atom economic transformation to construct useful aldehydes and is being industrially practiced for decades. The most commonly used metal for this transformation on an industrial scale is rhodium. However, rhodium is rare, costly, and is depleting at a skyrocketing rate. Therefore, finding a suitable alternative to rhodium for metal-catalyzed hydroformylation has been on the radar of many academic and industrial researchers. This review presents the scientific advancements reported in the hydroformylation reaction using metals other than rhodium. An overview of recent progress in palladium, iridium, ruthenium, cobalt, platinum, and iron-catalyzed hydroformylation is presented. Hydroformylation of alkenes and alkynes, using syngas as well as syngas surrogates is examined. The evaluation of the current status of non-rhodium metals in hydroformylation suggests that the field is still in a nascent stage and, except cobalt, no other metal poses a significant challenge to the dominance of rhodium. Deep mechanistic understanding of rate-limiting elementary steps in the non-rhodium metals is largely missing and thus only limited success is reported. Intense research on ligand design, mechanistic understanding, and choice of non-rhodium metal precursors may change this scenario in near future.10aaldehydes10aalkenes10acatalysis10aHydroformylation10aNon-rhodium metals1 aKumar, Rohit1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/hydroformylation-olefins-metals-other-rhodium02053nas a2200277 4500008004100000022001400041245011600055210006900171260000800240300001500248490000900263520112800272653002901400653001401429653001901443653002201462653003101484100001701515700001701532700002201549700001501571700001701586700001701603700002401620856013101644 2022 eng d a1434-193X00aMechanistically guided one pot synthesis of phosphine-phosphite and its implication in asymmetric hydrogenation0 aMechanistically guided one pot synthesis of phosphinephosphite a cJAN ae2021014470 v20223 a

Although hybrid bidentate ligands are known to yield highly enantioselective products in asymmetric hydrogenation (AH), synthesis of these ligands is an arduous process. Herein, a one pot, atom-economic synthesis of a hybrid phosphine-phosphite (L1) is reported. After understanding the reactivity difference between an 0-nucleophile versus C-nucleophile, one pot synthesis of Senphos (L1) was achieved (72%). When L1 was treated with [Rh], P-31 NMR revealed bidentate coordination to Rh. Senphos, in the presence of rhodium, catalyzes the AH of Methyl-2-acetamido-3-phenylacrylate and discloses an unprecedented turn over frequency of 2289, along with excellent enantio-selectivity (92%). The generality is demonstrated by hydrogenating an array of alkenes. The AH operates under mild conditions of 1-2 bar H-2 pressure, at room temperature. The practical relevance of Ll is demonstrated by scaling-up the reaction to 1 g and by synthesizing DOPA, a drug widely employed for the treatment of Parkinson's disease. Computational insights indicate that the R isomer is preferred by 3.8 kcal/mol over the S isomer.

10aasymmetric hydrogenation10acatalysis10aDOPA synthesis10aOne pot synthesis10aPhosphine-phosphite ligand1 aSen, Anirban1 aKumar, Rohit1 aPandey, Swechchha1 aRaj, Vipin1 aKumar, Pawan1 aVanka, Kumar1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/mechanistically-guided-one-pot-synthesis-phosphine-phosphite-and-its-implication-asymmetric02224nas a2200253 4500008004100000022001400041245010100055210006900156260000800225300001100233490000800244520136700252653002401619653003201643653002201675653002901697653002101726653001801747100002101765700001901786700002401805700001701829856012401846 2023 eng d a0022-328X00aComputational insights into the iron-catalyze d magnesium-me diate d hydroformylation of alkynes0 aComputational insights into the ironcatalyze d magnesiumme diate cFEB a1226210 v9863 a

Iron is one of the most abundant transition metals in the earth's crust. It has attracted a lot of attention due to its low toxicity, bio-compatibility, and high natural abundance. Iron-catalyzed hydroamination, hydroalkoxylation, hydrocarboxylation, hydrosilylation, hydroboration, hydrophosphination, hydromagnesiation, and carbonylation reactions have therefore been developed over the past decades. However, despite many experimental and theoretical studies, a complete mechanistic understanding of iron-catalyzed hydrofunctionalisation at the molecular level has not yet been achieved. In this work, through density functional theory (DFT) calculations, we have shown the most feasible path for the hydroformylation of alkynes for an experimentally studied system. We have looked at the iron salt as a precatalyst without any external donor ligand, and the calculations revealed that hydrometalation followed by beta-hydride elimination was favorable over the direct migration of the beta-hydrogen to carbon. Furthermore, our calculations show that the solvent plays an important role in the hydromagnesiation reaction. Furthermore, we have employed an explicit solvent model, where the attachment of one molecule of solvent to the iron center was seen to stabilize the transition states significantly.(c) 2023 Elsevier B.V. All rights reserved.

10aComputational study10aEthylene Assisted Catalysis10aEtMgBr Assistance10aExplicit Role of Solvent10aHydroformylation10aIron Catalyst1 aSharma, Himanshu1 aTewari, Tanuja1 aChikkali, Samir, H.1 aVanka, Kumar uhttps://library.ncl.res.in/content/computational-insights-iron-catalyze-d-magnesium-me-diate-d-hydroformylation-alkynes02389nas a2200265 4500008004100000022001400041245006000055210005900115260000800174300001200182490000700194520158300201653001901784653002801803653003301831653002301864653001101887100002701898700002401925700001801949700002401967700001901991700002402010856008902034 2023 eng d a1060-132500aEmerging trends in olefin polymerization: a perspective0 aEmerging trends in olefin polymerization a perspective cNOV a731-7500 v603 a

The seemingly matured field of olefin polymerization still poses several challenges and holds enormous potential to meet contemporary material requirements. In this feature article, we examine the progress of olefin polymerization in the last two decades. Among the several emerging trends, we identify four most impactful discoveries, namely, (i) disentangled ultra-high molecular weight polyethylene (dUHMWPE), (ii) disubstituted functional olefin copolymerization, (iii) incorporation of bioderived comonomers in polyolefins, and (iv) application of above (ii, iii) functional polyolefins as compatibilizers. The dUHMWPE has attracted significant attention and heterogeneous Ziegler-type catalysts, homogenous metallocene, and post-metallocene catalysts have been reported to produce disentangled ultrahigh molecular weight polyethylene. Insertion copolymerization of difunctional disubstituted olefins has been reported only recently and ortho-phosphinobenzene sulfonate palladium catalyst outperforms the other catalysts. Interestingly, insertion copolymerization of bioderived olefins has witnessed a surge in the number of reports. Sugar and plant oil-derived olefins have been copolymerized with ethylene to obtain relatively hydrophilic polyethylene. The functional polyethylene is finding a new application as compatibilizer or displays better adhesion to surfaces. Thus, the feature article offers a succinct account of emerging trends in polyolefins, identifies the most impactful contributions, and debates the application potential of these new materials.

10acompatibilizer10aFunctional polyethylene10aInsertion (co)polymerization10arenewable monomers10auHMWPE1 aBirajdar, Rajkumar, S.1 aBodkhe, Dnyaneshwar1 aGupta, Poonam1 aShaikh, Maulali, H.1 aRamekar, Rohan1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/emerging-trends-olefin-polymerization-perspective02074nas a2200169 4500008004100000022001400041245009400055210006900149260000900218300001400227490000700241520147300248100001901721700001701740700002401757856012301781 2023 eng d a2044-475300aIron-catalysed highly selective hydroalkoxycarbonylation of alkynes using CO as C1 source0 aIroncatalysed highly selective hydroalkoxycarbonylation of alkyn cOCT  a5549-55550 v133 a

Though precious and rare, late-transition metals have been extensively used in metal-catalysed carbonylation reactions in organic transformations. On the other hand, base metals are abundant and cheap, but their practical utilization in carbonylation reactions is rarely explored. Here, we report iron-catalysed hydroalkoxycarbonylation of alkynes to alpha,beta-unsaturated esters in one pot. A readily available iron precursor [Fe2(CO)9] in the presence of a diimine ligand L7 catalyzes the conversion of alkynes to alpha,beta-unsaturated esters under 10 bar CO pressure. This operationally simple protocol tolerates various functional groups and allows facile access to about 40 alpha,beta-unsaturated esters. The synthetic utility of the reaction has been demonstrated by scaling up the reaction to 1 g and by preparing sunscreen/antifungal agents. The kinetic study suggests that the reaction is an approximate 1st order with respect to the iron catalyst, and the initial rate of the reaction is 3.6 x 10-2 M h-1. Mechanistic investigations using NMR spectroscopy indicated the existence of an [Fe-H] intermediate, and control experiments using a radical trapping reagent and EPR revealed the absence of any radical species in the reaction. Precious and rare, late transition metals have been extensively used in carbonylation. An earth abundant iron-catalyst is reported here for hydroalkoxycarbonylation of alkynes in the presence of CO as C1 source.

1 aTewari, Tanuja1 aKumar, Rohit1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/iron-catalysed-highly-selective-hydroalkoxycarbonylation-alkynes-using-co-c1-source02091nas a2200241 4500008004100000022001400041245010400055210006900159260000900228490000700237520124700244653001701491653003501508653002901543653003301572653001801605100001701623700001701640700001901657700002401676700002401700856012501724 2023 eng d a0947-653900aIron-catalyzed alkoxylation, dehydrogenative-polymerization and tandem hydrosilylative-alkoxylation0 aIroncatalyzed alkoxylation dehydrogenativepolymerization and tan cAUG 0 v293 a

Alkoxylation, hydrosilylative-alkoxylation, and dehydrogenative-polymerization are some of the most widely used transformations in synthetic chemistry. However, these transformations are traditionally catalyzed by precious, and rare late-transition metals. Presented here is a molecularly defined iron complex that catalyzes alkoxylation, tandem hydrosilylative-alkoxylation, and dehydrogenative polymerization of silanes under mild conditions. The iron complex [Fe(CO)(4)(H)(SiPh3)] 1 catalyzes a direct Si-O coupling reaction between an array of silanes and alcohols to produce desired alkoxysilanes in excellent yield, with H-2 as the only byproduct. The iron catalyst tolerates various functional groups and provides access to 20 alkoxysilanes, including essential molecules such as & beta;-citronellol and cholesterol. Further, complex 1 catalyzes the polymerization of renewable diol and silane monomer to produce a renewable and degradable poly(isosorbide-silyl ether). Remarkably, complex 1 catalyzes a tandem hydrosilylative-alkoxylation of alkynes under mild conditions to yield unsaturated silyl ethers. The synthetic utility has been demonstrated by gram-scale alkoxylation and hydrosilylative-alkoxylation reactions.

10aalkoxylation10adehydrogenative polymerization10aearth abundant catalysts10ahydrosilylative-alkoxylation10aIron Catalyst1 aSen, Anirban1 aKumar, Rohit1 aTewari, Tanuja1 aGonnade, Rajesh, G.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/iron-catalyzed-alkoxylation-dehydrogenative-polymerization-and-tandem-hydrosilylative01926nas a2200217 4500008004100000022001400041245008500055210006900140260000900209490000700218520122800225653001401453653001201467653001201479653002101491653001901512100001901531700001701550700002401567856011701591 2023 eng d a1867-388000aIron-catalyzed magnesium-mediated formal hydroformylation of alkynes and alkenes0 aIroncatalyzed magnesiummediated formal hydroformylation of alkyn cFEB 0 v153 a

Alkynes and alkenes are routinely converted to corresponding synthetically versatile aldehydes using rhodium-catalyzed hydroformylation. However, rhodium is rare, precious, costly, and depleting at a considerably high rate. Reported here is iron-catalyzed, magnesium-mediated, formal hydroformylation of alkynes and alkenes in the absence of syngas. Readily available FeCl2 in the presence of alkyl magnesium halide, and dimethyl formamide, catalyzes hydroformylation of various alkynes and selectively produces alpha,beta-unsaturated aldehydes in good to excellent conversion. Mechanistic investigations revealed the presence of vinyl magnesium intermediate, the kinetic study disclosed the first-order dependence of the reaction on iron loading, and the control experiment authenticated the iron catalyst's homogeneous nature. The scope of this methodology was amplified, and 20 alkenes were examined. [Fe(acac)(3)] in the presence of ligand, alkyl magnesium halide, and dimethyl formamide catalyzed the hydroformylation of alkenes and displayed good to excellent conversion. An earth-abundant iron catalyst offering a syngas cylinder-free safe alternative to high-pressure hydroformylation has been reported.

10aaldehydes10aalkenes10aAlkynes10aHydroformylation10airon catalysis1 aTewari, Tanuja1 aKumar, Rohit1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/iron-catalyzed-magnesium-mediated-formal-hydroformylation-alkynes-and-alkenes02129nas a2200157 4500008004100000245004500041210004400086260000800130300001100138490000600149520166800155100002401823700002401847700002001871856008001891 2023 eng d00aMetal-catalyzed plastic depolymerization0 aMetalcatalyzed plastic depolymerization cMAY a1013410 v43 a

Polymers have become an indispensable part of our daily lives, and today we produce around 370 MT of plastic per year. Only about 20% of it is being recycled, and the rest, 80%, is unleashed into the environment without appropriate treatment. This calls forth the evaluation of strategies available for mitigating the menace of ``after-use''plastic waste. Various approaches have evolved over a decade and are at different levels of development. Plastic depolymerization and upcycling are considered some of the most prominent and long-term solutions. The metal-catalyzed depolymerization of plastic waste to chemical feedstocks has emerged as one of the promising ways to address global plastic pollution. Therefore, this review aims to examine the available metal-catalyzed depolymerization methods, notify recent progress, pinpoint current gaps, and gauge the potential of this strategy. Both homogeneous and heterogeneous catalysts have been reported to depolymerize various polymers over the last decade. Considerable advances have been reported in the metal-mediated depolymerization of polyolefins, polyesters, polycarbonates, polyurethanes, polyamides, and polyethers. The depolymerization of the above polymers produces the monomers or intermediates, which can be used again for polymerization and thus brings the waste polymers back into circularity. The overview debates the usage of high temperaagents, etc., in metal-catalyzed depolymerization. Thus, this review summarizes the current understanding of the fundamental science of metal-catalyzed plastic depolymerization, the remaining scientific challenges, and the potential opportunities.

1 aKhopade, Kishor, V.1 aChikkali, Samir, H.1 aBarsu, Nagaraju uhttps://library.ncl.res.in/content/metal-catalyzed-plastic-depolymerization02263nas a2200217 4500008004100000022001400041245011800055210006900173260000800242300001400250490000700264520147700271100002701748700002401775700002701799700001901826700002201845700002301867700002401890856013101914 2023 eng d a1759-995400aPalladium-catalyzed polar solvent empowered synthesis of hyper-branched ethylene oligomers and their applications0 aPalladiumcatalyzed polar solvent empowered synthesis of hyperbra cJUL a3239-32510 v143 a

In this contribution, we report the synthesis of two naphthoxy imine ligands, 2-(((2,6-dibenzhydryl-4-methoxyphenyl)imino)methyl)naphthalen-1-ol (L1) and 2-(((2,6-diisopropylphenyl)imino)methyl)naphthalen-1-ol (L2), with different steric and electronic features. L1 and L2 were treated with [(TMEDA)PdMe2] to obtain the corresponding neutral palladium(ii) complexes Cat.1 and Cat.2 in excellent yields. The identity of Cat.1 and Cat.2 was unambiguously ascertained using a combination of spectroscopic and analytical methods, including single-crystal X-ray diffraction. When exposed to 5 bar ethylene pressure, Cat.1 produced hyperbranched ethylene oligomers. The microstructure analysis of ethylene oligomers confirmed the existence of methyl, ethyl, propyl, and sec-butyl branches, with a molecular weight (M-n) of 500-1400 g mol(-1), a PDI of 1.46-2.10, and 67-106 branches per 1000 carbon atoms. The use of a polar solvent, tetrahydrofuran, led to a remarkable 3-fold increase in oligomerization activity without compromising the branching and molecular weight. The resultant hyperbranched ethylene oligomers were selectively monofunctionalized using industrially practiced hydroformylation, ozonolysis, and epoxidation, almost quantitatively. The hydroxy functionalized ethylene oligomer (F4) (5 wt%) was melt-compounded with LLDPE and Nylon-6 to produce a tough yet flexible blend with a higher strain-to-failure as compared to an uncompatibilized blend.

1 aBirajdar, Rajkumar, S.1 aGonnade, Rajesh, G.1 aPol, Harshawardhan, V.1 aPrabhu, Basava1 aRokade, Dhammaraj1 aNandimath, Sheetal1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/palladium-catalyzed-polar-solvent-empowered-synthesis-hyper-branched-ethylene-oligomers-and01965nas a2200253 4500008004100000022001400041245011400055210006900169260000800238300001400246490000600260520113300266653001301399653000901412653001801421653001701439653001901456100001801475700002001493700002201513700002401535700002701559856012501586 2023 eng d a2637-610500aPolyethylene-grafted sheet-like silsesquioxane nanocomposites with unprecedented adhesion to polar substrates0 aPolyethylenegrafted sheetlike silsesquioxane nanocomposites with cJUL a5972-59830 v53 a

Polyethylene is a highly apolar polymer with very pooradhesionto most substrates, necessitating the use of tie layers. Therefore,the synthesis of functional polyethylene is a long-standing challengein catalytic ethylene polymerization. Here, we report the preparationof a nanocomposite comprising polyethylene covalently grafted ontosheet-like silsesquioxanes, with unprecedented adhesion to metal andglass. A norbornene-grafted, layered Mg-silsesquioxane is treatedwith Grubbs second-generation catalyst (G-II), and the identity ofcovalently tethered G-II is unambiguously ascertained. Covalentlytethered G-II catalyzes the ring opening metathesis polymerizationof cyclooctene to poly(cyclooctene). The resulting poly(cyclooctene)is catalytically hydrogenated to yield polyethylene. This polyethylenenanocomposite exhibited a bonding strength of the order of 100 MPaon stainless steel and aluminum, 10-fold higher than reported forengineered polyethylene copolymers. The nanocomposite exhibits anincrease in the polar component of surface energy, yet remains compatibleand cocrystallizes with a polyethylene matrix.

10aadhesion10aclay10aNanocomposite10aPolyethylene10asilsesquioxane1 aSharma, Vivek1 aPaulbudhe, Uday1 aBachhar, Nirmalya1 aChikkali, Samir, H.1 aKumaraswamy, Guruswamy uhttps://library.ncl.res.in/content/polyethylene-grafted-sheet-silsesquioxane-nanocomposites-unprecedented-adhesion-polar01984nas a2200229 4500008004100000022001400041245008100055210006900136260000900205300000800214490000800222520124900230653001401479653001701493653002101510653003101531653002101562100001701583700001701600700002401617856011301641 2023 eng d a0974-362600aRh-catalyzed asymmetric hydroformylation of olefins using phosphorus ligands0 aRhcatalyzed asymmetric hydroformylation of olefins using phospho cNOV  a1080 v1353 a

Easily accessible BINOL-based monodentate phosphite ligand L1 and hybrid ligand L2 have been synthesized in good yield by following a one-pot, two-step protocol. A single 31P resonance at 146.6 ppm confirmed the formation of L1. Subsequent 1-2D NMR and mass spectrometric analysis authenticated the existence of L1. These ligands afforded excellent activity and regio-selectivity in the Rh-catalyzed AHF of styrenic substrates. L1 showed excellent regioselectivity but did not discriminate between the two enantiomers, while L2 displayed an enantiomeric excess (ee) of up to 20%. In our attempts to understand the reasons for low ee, the coordination behavior of L2 was investigated. The coordination study revealed that L2 coordinates with the Rh as a monodentate ligand, although there are two P-sites. It was found that only the phosphine arm was coordinated to the Rh and the phosphite arm stayed away from the Rh core at the ambient temperature, leading to moderate ee.Graphical abstractOne-step synthesis of a phosphite (L1) and a phosphine-phosphite (L2) ligand and their implication in the asymmetric hydroformylation of olefins with excellent regioselectivity (>95%) and moderate enantioselectivity (up to 20%) is reported.

10acatalysis10acoordination10aHydroformylation10aPhosphine-phosphite ligand10aPhosphite ligand1 aKumar, Rohit1 aSen, Anirban1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/rh-catalyzed-asymmetric-hydroformylation-olefins-using-phosphorus-ligands02256nas a2200157 4500008004100000022001400041245013800055210006900193260000900262300001100271490000800282520163100290100002801921700002401949856012501973 2023 eng d a0014-305700aTi-iminocarboxylate catalyzed polymerization of ethylene to highly crystalline, disentangled, ultrahigh molecular weight polyethylene0 aTiiminocarboxylate catalyzed polymerization of ethylene to highl cJAN  a1117250 v1823 a

Disentangled ultrahigh molecular weight polyethylene (d-UHMWPE) is a niche, highly sought-after, and an emerging class of polyethylene. However, the synthesis of d-UHMWPE is uncommon and is equally challenging. Here, we report a Ti-iminocarboxylate complex that produces d-UHMWPE under ambient polymerization conditions. Treatment of tetrakis(dimethylamido-titanium) [Ti(NMe2)4] with 2-((4-methoxybenylidene)amino)benzoic acid produced a novel titanium complex Cat.1 [bis-dimethylamido-Ti-(bis-iminocarboxylate)]. The identity of Cat.1 was unambiguously ascertained using a combination of 1-2D NMR spectroscopy and mass analysis. Cat.1 was activated using various cocatalysts, and MMAO (modified methylaluminoxane) outperformed the others. Screening of polymerization parameters suggested an Al/Ti ratio of 1000, 4 bar ethylene pressure, 35 degrees C temperature, and a polymerization time of 30 min as the optimal condition. Under the optimized polymerization conditions, Cat.1 polymerizes ethylene to ultrahigh molecular weight polyethylene with a weight average molecular weight (Mw) of 2.5 x 106 g/mol. The thermal behavior of the thus prepared material disclosed a highly crystalline [crystallinity chi (DSC) 96 %], strictly linear polyethylene. Detailed thermal analysis of the nascent polyethylene using a specifically designed DSC method revealed the existence of a high melting peak at 139-140 degrees C, which is a hallmark of disen-tangled UHMWPE. Thus, a homogeneous, single-site ethylene polymerization catalyst has been developed, which upon activation with MMAO produced highly crystalline d-UHMWPE.

1 aBodkhe, Dnyaneshwar, V.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/ti-iminocarboxylate-catalyzed-polymerization-ethylene-highly-crystalline-disentangled02091nas a2200193 4500008004100000022001400041245010700055210006900162260000800231300001600239490000700255520138000262100002401642700002401666700003101690700002001721700002401741856013201765 2024 eng d a1463-926200aDepolymerization of waste polyethylene to linear alkenes via sequential dehydrogenation and metathesis0 aDepolymerization of waste polyethylene to linear alkenes via seq cOCT a10558-105660 v263 a

Polyethylene (PE) is the most abundantly sourced plastic and significant efforts are needed for its end-of-life management. The deconstruction of PE is an uphill task and requires the breaking of highly stable C-C bonds. Here we demonstrate that PE can be deconstructed to value-added dodecene, along with other long-chain alkenes. The PCP-iridium complex catalyzes the dehydrogenation of commercial and post-consumer polyethylene waste to produce dehydrogenated polyethylene (DHP) with 0.5-1.0% unsaturation. The DHP was subjected to an ethylene cross-metathesis reaction in the presence of suitable catalysts. Through meticulous optimization of reaction parameters, 63% selectivity toward dodecene, with 26% overall yield, was achieved. The practical significance of our method has been demonstrated by subjecting post-consumer plastic waste to dehydrogenation followed by ethylene metathesis to produce dodecene as a major product, together with long-chain alkenes. The PE deconstruction has been confirmed by recording molar mass before and after depolymerization using high-temperature gel permeation chromatography. The existence of dodecene has been unambiguously ascertained using GC, GC-MS, NMR, and IR spectroscopy. Thus, these results demonstrate the conversion of waste PE to value-added dodecene and long-chain alkenes under mild reaction conditions.

1 aKhopade, Kishor, V.1 aRajput, Nikhita, S.1 aRangappa, Raghavendrakumar1 aBarsu, Nagaraju1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/depolymerization-waste-polyethylene-linear-alkenes-sequential-dehydrogenation-and-metathesis02488nas a2200277 4500008004100000022001400041245010000055210006900155260000800224520154900232653001701781653000801798653003001806653002701836653001701863100002401880700001901904700002101923700002101944700002801965700002201993700002502015700001702040700002402057856012902081 2024 eng d a1060-132500aDesigning of imine thiophene-ligated metal-complexes and implication in ethylene polymerization0 aDesigning of imine thiopheneligated metalcomplexes and implicati cSEP3 a

Polyethylene is the single largest volume polymer produced globally using Ziegler-type catalysts. Numerous modifications have been reported in search of a better catalyst that can control molecular weight, polydispersity, and branching. In our attempts to identify a suitable imine thiophene-ligated chromium complex, we examined 9 different titanium complexes computationally. The DFT investigations considered barriers for insertion, propagation, and termination by beta-H elimination or chain transfer, and identified N-(4-methoxyphenyl)-2-phenyl-1-(thiophen-2-yl)ethan-1-imine(L9) as the most suitable ligand. Subsequently, L9 was prepared in good yield (70%) by condensing 2-phenyl-1-(thiophen-2-yl)ethan-1-one with 4-methoxyaniline. Ligand L9 was treated with early transition metal precursors (Ti, Cr, Zr) to generate a homogenous catalyst. The identity of these catalysts was unambiguously ascertained using a combination of NMR, ICP, FT-IR, UV-Vis spectroscopy, and ESI-MS. The performance of L9-ligated titanium complex [Cat.1] was examined in ethylene polymerization using MMAO as a co-catalyst. Insertion of ethylene was tracked using high-pressure NMR experiments and Cat.1 was found to be active in the polymerization. Ethylene polymerization conditions were optimized to obtain high activity and molecular weight polyethylene. The chromium complex [Cat.2] outperformed the Ti and Zr-derived catalysts with the highest TOF of 6294 mol of PE/mol of Cr/h. Cat.2 produced high molecular weight, high-density polyethylene.

10aCr-complexes10aDFT10ahigh-density polyethylene10aImine thiophene ligand10aPolyethylene1 aShaikh, Maulali, H.1 aRamekar, Rohan1 aJawoor, Shailaja1 aDash, Soumya, R.1 aBirajadar, Rajkumar, S.1 aPawal, Sandip, B.1 aThenmani, Nandakumar1 aVanka, Kumar1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/designing-imine-thiophene-ligated-metal-complexes-and-implication-ethylene-polymerization02612nas a2200241 4500008004100000022001400041245008600055210006900141260000900210490000700219520183600226653002502062653001102087653001802098653002102116653002302137653002002160653001902180100001702199700001902216700002402235856011102259 2024 eng d a1867-388000aIron in organometallic transformations: a sustainable substitute for noble metals0 aIron in organometallic transformations a sustainable substitute  cOCT 0 v163 a

Transition metal catalysis plays a pivotal role in chemical synthesis. Noble metals often grab significant attention in organometallic catalysis due to their high reactivity. However, the serious issues associated with these metals such as low abundance, toxicity, geopolitical limitations, and volatile prices are driving the scientific community to discover sustainable alternatives. In this context, iron appears to be the first choice as an alternative metal due to its unique properties, including a range of stable oxidation states, Lewis acidity, high abundance in the earth's crust, and low toxicity. Over the past two decades, substantial progress has been made in iron catalysis. This overview examines the recent developments in iron-catalyzed industrially relevant transformations such as hydroformylation, olefin isomerization, hydrosilylation, hydrophosphination, carbonylation, Wacker-type oxidation, and plastic depolymerization. As witnessed throughout this review, the performance of iron can be significantly altered by suitable ligand selection and by tailoring the electronic and steric properties of the iron center. While noble metals remain the industry work-horse, iron is inching closer and with extensive scientific understanding, it may replace noble metals in the near future. Late transition metals catalyze several reactions and have been the industry work-horse for decades. While, earth abundant metals are rarely used in industrially relevant transformations. In this overview, we examine the recent development in iron-catalyzed industrially relevant reactions such as hydroformylation, olefin isomerization, hydrosilylation, hydrophosphination, carbonylation, Wacker-type oxidation, and plastic depolymerization. Iron is inching closer and may replace noble metals in near future. image

10aAlkene Isomerization10aalkyne10aCarbonylation10adepolymerization10aHydrophosphination10aHydrosilylation10airon catalysis1 aKumar, Rohit1 aTewari, Tanuja1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/iron-organometallic-transformations-sustainable-substitute-noble-metals02631nas a2200205 4500008004100000022001400041245009200055210006900147260000800216490000700224520194000231100001702171700001902188700001702207700001802224700002102242700001702263700002402280856012102304 2024 eng d a2044-475300aIron-catalyzed (E)-selective hydrosilylation of alkynes: scope and mechanistic insights0 aIroncatalyzed Eselective hydrosilylation of alkynes scope and me cMAY0 v143 a

Iron-catalyzed hydrosilylation of internal alkynes has been rarely reported. Even in these rare cases, additives have been used for the success of the reaction, which often creates a problem for the functional group tolerance of the reaction. Herein, we report an additive-free iron-catalyzed (E)-selective hydrosilylation of internal alkynes in the presence of a phosphine ligand. A low-valent Fe(0) complex [Fe(CO)(3)(BDA)] {[Fe-1]} catalyzed the hydrosilylation of alkynes at 60 to 120 degrees C, exhibited a broad substrate (24 substrates) scope and tolerated different functional groups. The synthetic utility of the reaction was demonstrated by a gram scale experiment, preparing alkenes, and by chemo-selective hydrosilylation. The modus operandi of the reaction has been investigated by i) homogeneity test, ii) radical trapping experiments, iii) X-ray photoelectron spectroscopy, and iv) by preparing a Fe(II) complex as catalyst control. These mechanistic investigations revealed a two-electron pathway for the hydrosilylation of alkynes. In addition, kinetic investigations were undertaken to shed light on the rates of the reaction. Kinetic studies suggest the absence of an induction period, and the reaction is first order with respect to the concentration of iron catalyst [Fe-1] and zeroth order with respect to the substrate (alkyne). The Hammett plot suggests that strongly electron-withdrawing groups on the alkyne favour the hydrosilylation reaction. Meanwhile Eyring analysis suggests that the rate-determining step likely involves an associative pathway. Based on the findings of the mechanistic and kinetic investigation, a plausible Chalk-Harrod-type mechanism is likely to be operative. The proposed mechanism is substantiated by computational investigations, which suggested that the Chalk-Harrod mechanism is kinetically more favored by 15.8 kcal mol(-1) over the modified Chalk-Harrod mechanism.

1 aSen, Anirban1 aTewari, Tanuja1 aKumar, Rohit1 aVinod, C., P.1 aSharma, Himanshu1 aVanka, Kumar1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/iron-catalyzed-e-selective-hydrosilylation-alkynes-scope-and-mechanistic-insights02241nas a2200181 4500008004100000022001400041245006400055210006200119260000800181300001600189490000700205520166600212100001801878700002601896700002101922700002401943856009201967 2024 eng d a1144-054600aLinear poly(lactic acid) ionomers with pendant ionic groups0 aLinear polylactic acid ionomers with pendant ionic groups cDEC a20304-203160 v483 a

Although PLA is widely used, melt processing of this polymer is still a challenging task. In our efforts to improve the melt strength and processability of PLA, we report the synthesis of high molecular weight linear PLA ionomers. PLA copolymers (CP1-CP3) with pendant alkyne groups were synthesized by reacting L-lactide with propargylated lactide. The existence of copolymers with alkyne groups was unambiguously demonstrated, and the percentage of alkyne was found to be 3-7%. A click reaction protocol was developed to treat the resultant alkyne functionalized copolymers (CP1-CP3) with mercaptosuccinic acid (MSA) and pendant carboxylic acid group functionalized copolymers (CP1-MSA1 to CP3-MSA3) were obtained. The 1-2D NMR confirmed the formation of a major MSA bis-addition product, along with a minor mono-addition product. In the final step, the MSA functionalized copolymers were treated with sodium hydride (NaH) to obtain the corresponding linear PLA ionomers (CP1-MSA1-Na1 to CP3-MSA3-Na3). Significant improvement in thermal and melt rheological properties was observed in these ionomers, as compared to the precursor copolymer and unmodified PLA, due to the microstructural changes caused by the association of the ionic groups. Storage modulus (G `) and loss modulus (G `') values showed a substantial increase in melt elasticity of the ionomers with G ` > G `', whereas the unmodified PLA melt behaved like a viscoelastic liquid. Detailed investigation reveals that incorporating pendant ionic groups in a high molecular weight linear PLA remarkably enhances the elastic modulus from 10 to 100 000 Pa (four orders of magnitude).

1 aJoseph, Seena1 aMenon, Abhijith, Hari1 aLele, Ashish, K.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/linear-polylactic-acid-ionomers-pendant-ionic-groups02488nas a2200205 4500008004100000022001400041245012100055210006900176260000900245300001200254490000700266520172700273653003602000653002102036653002102057100002702078700002402105700002402129856012902153 2024 eng d a1759-995400aRegulating the polyethylene microstructure by increasing steric crowding in naphthoxy imine-ligated Ni(II) complexes0 aRegulating the polyethylene microstructure by increasing steric  cJAN  a292-3020 v153 a

Ligands play a prominent role in ethylene polymerization. However, it is a highly challenging task to regulate branching through ligand modifications. Here we report the synthesis of systematically sterically tailored naphthoxy imine-ligated nickel complexes (Ni1, Ni2, and Ni3), their performance in ethylene polymerization, and how the ligand steric controls branching in the resultant PE. Ni1-Ni3 were prepared in one step with an excellent yield (73-93%). The identity of these complexes was unambiguously ascertained using H-1, C-13, 2D NMR spectroscopy, mass analysis, and single-crystal X-ray diffraction. The molecular structure revealed a cis arrangement of alkyl/aryl and donor groups (C-Ni-D), which is necessary for initiating ethylene polymerization. Buried volume contours suggested Ni3 to be sterically the most bulky among the three. When exposed to ethylene, the three nickel complexes Ni1, Ni2, and Ni3 produced polyethylene with excellent activity. As predicted by buried volume calculations, dibenzhydryl-substituted Ni3 outperformed sterically less crowded Ni1 and Ni2. Careful analysis of the resultant PE disclosed that sterically less encumbered Ni1 and Ni2 produce PE with high branching (43-54 branches/1000-C atoms) density. However, the bulkiest Ni3 revealed much lower branching (28 branches/1000-C atoms) and a high TOF of 35 400 mol of PE per mol of Ni per h, along with a high molecular weight of PE (61 000 Da). The steric bulk in Ni3, most likely, reduces chain-walking and thus lowers branching in the resultant PE. As compared to the literature-reported analogous Pd1 catalyst, the Ni3 catalyst discloses high TOF, high molecular weight, and less branched, linear polyethylene.

10aCatalyzed Olefin Polymerization10aHigh-Temperature10aMolecular Weight1 aBirajdar, Rajkumar, S.1 aGonnade, Rajesh, G.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/regulating-polyethylene-microstructure-increasing-steric-crowding-naphthoxy-imine-ligated00836nas a2200229 4500008004100000022001400041245011000055210006900165260000900234300001400243490000700257653001700264653003400281100002600315700002200341700001900363700002700382700002400409700002500433700002200458856012600480 2024 eng d a2155-543500aSolvent-free hydroxylation of unactivated C-H bonds in small molecules and macromolecules by a Fe complex0 aSolventfree hydroxylation of unactivated CH bonds in small molec cAPR  a7173-71810 v1410aBall milling10asolid-state C-H hydroxylation1 aChatterjee, Debasmita1 aSajeevan, Amritha1 aJana, Sandipan1 aBirajdar, Rajkumar, S.1 aChikkali, Samir, H.1 aSivaram, Swaminathan1 aGupta, Sayam, Sen uhttps://library.ncl.res.in/content/solvent-free-hydroxylation-unactivated-c-h-bonds-small-molecules-and-macromolecules-fe02140nas a2200181 4500008004100000022001400041245009300055210006900148260000900217300001000226490000700236520150100243100002701744700001801771700002401789700002401813856012101837 2024 eng d a0020-166900aSynthesis of imine-phenoxy ligated palladium complexes for norbornene homopolymerization0 aSynthesis of iminephenoxy ligated palladium complexes for norbor cDEC  a25-360 v643 a

Metal complexes with tunable ligands play a crucial role in olefin polymerization and impart control over molecular weight, crystallinity, and stereoregularity. We report the single-step synthesis of imine-phenoxy ligands in excellent yields (81-93%). The identity of electronically tuned imine-phenoxy ligands was unambiguously ascertained by using a combination of spectroscopic and analytical methods. These ligands were treated with [Pd(COD)MeCl] in the presence of 2,6-lutidine, resulting in the formation of discrete mononuclear palladium complexes Pd1-Pd4 in excellent yields. 1-2D NMR spectroscopy, mass spectrometry analysis, and single-crystal X-ray diffraction confirmed the identity of the palladium complexes. X-ray analysis revealed a distorted square planar geometry around the palladium center. Proton NMR analysis suggested that the Pd1 catalyst was deshielded, indicating electronically deficient palladium metal compared to the other complexes. Moreover, the Pd1 catalyst showed the highest buried volume percentage (%Vbur = 44.9). When exposed to norbornene, Pd1-Pd4 were found to be active and produced poly(norbornene) (PNB). High-temperature SEC analysis revealed that the electronically deficient and sterically hindered Pd1 catalyst produced the highest molecular weight polymer (PNB 37.4 kDa). Boron and aluminum-based cocatalysts were screened, and MMAO was found to outperform others with high catalytic activity (up to 63.2 x 105 g of PNB (mol Pd)-1 h-1).

1 aBirajdar, Rajkumar, S.1 aGupta, Poonam1 aGonnade, Rajesh, G.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/synthesis-imine-phenoxy-ligated-palladium-complexes-norbornene-homopolymerization02297nas a2200217 4500008004100000022001400041245013400055210006900189260000900258490000700267520147200274653002901746653002901775653002301804653001801827653002901845100002701874700002401901700002401925856013001949 2024 eng d a0947-653900aThermally stable P-chiral supramolecular phosphines, their self-assembly and implication in Rh-catalyzed asymmetric hydrogenation0 aThermally stable Pchiral supramolecular phosphines their selfass cAUG 0 v303 a

P-chiral supramolecular phosphine ligands are crucial for asymmetric transformations, but their synthesis is tedious. We report a one-step synthesis of thermally stable P-chiral supramolecular phosphines and their performance in the asymmetric hydrogenation of functionalized alkenes. A rational designing and synthesis of (R, R)-QuinoxP* ligated palladium complex (Pd-2) in excellent yield is reported. This Pd-2 catalyzed a direct P-C coupling of 2,3-dihydro-1-H-phosphindole (A1)/1,2,3,4-tetrahydrophosphindoline (A2) with 1-(3-iodophenyl)urea (B1)/2-iodo /6-hydroxy pyridine (B2) and,produced corresponding ligands L1-L3. The P-C coupling between A1 and B2 produced 6-(2,3-dihydro-1H-phosphindol-1-yl)pyridine-2(1H)-one (L2) with an excellent enantiomeric excess of up to 99 %. L2 was found to be remarkably stable even at 150 degrees C and did not oxidize/hydrolyze for at least 24 hours in open air. Such thermal stability and an impediment to oxidation are unprecedented. L2 self-assembled and produced L2-C1 (Pt), L2-C2(Pd), and L2-C3(Rh) assemblies. The utility of the self-assembled P-chiral ligand was demonstrated in the Rh-catalyzed asymmetric hydrogenation (AH) of functionalized olefins. The L2-C3 catalyzed AH of functionalized alkenes and delivered chiral products with excellent enantioselectivity of >99 %. A small library of 16 substrates was subjected to AH using L2-C3 to produce chiral compounds with excellent conversion and ee.

10aasymmetric hydrogenation10aAsymmetric phosphination10aP-chiral phosphine10aSelf-assembly10aSupramolecular phosphine1 aChandanshive, Amol, C.1 aGonnade, Rajesh, G.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/thermally-stable-p-chiral-supramolecular-phosphines-their-self-assembly-and-implication-rh02202nas a2200265 4500008004100000022001400041245011700055210006900172260000800241490000700249520127100256653001701527653003001544653002601574653002301600653002801623100002101651700001601672700003101688700002001719700001701739700002401756700002401780856013201804 2025 eng d a0947-653900aElectrochemical deconstruction of waste polyvinylidene chloride (PVDC) to value-added products in batch and flow0 aElectrochemical deconstruction of waste polyvinylidene chloride  cFEB0 v313 a

Chlorinated polymers have made enormous contributions to materials science and are commercially produced on a large scale. These chlorinated polymers could be recycled as chlorine sources to efficiently produce valuable chlorinated compounds owing to their facile release of HCl. Although the thermal stability of PVDC is low compared to PVC, this can be advantageous in terms of easy and fast dehydrochlorination. Herein, we report an efficient electrochemical chlorination using poly(vinylidene chloride) (PVDC) as a chlorine source that works in an undivided cell and applies to a good number of examples. This method works on commodity polymers such as waste PVDC-PVC pharma blister film, PVDC-PO multilayer food packaging, and compression molded sheets of Ixan PVDC (with heat stabilizer) with similar efficiency. Furthermore, this method also provides the dechlorination of PVDC up to 98 %, leading to unsaturated dechlorinated material. Converting PVDC into more stable unsaturated compounds, the release of harmful chlorine-containing gases during incineration can be minimized. Additionally, this method is not only restricted to batch processes but an electroflow process for PVDC dechlorination and electrosynthesis has also been demonstrated.

10achlorination10aElectrochemical recycling10aElectroflow-synthesis10aGraphitic material10aPolyvinylidene chloride1 aMishra, Subhadip1 aKar, Sourav1 aRangappa, Raghavendrakumar1 aPatil, Prashant1 aKadam, Vijay1 aChikkali, Samir, H.1 aSamanta, Ramesh, C. uhttps://library.ncl.res.in/content/electrochemical-deconstruction-waste-polyvinylidene-chloride-pvdc-value-added-products-batch01792nas a2200241 4500008004100000022001400041245009600055210006900151260000800220490000700228520099400235653001901229653002601248653001901274653001701293653001401310100001901324700002401343700002101367700001701388700002401405856012101429 2025 eng d a2193-580700aIron-catalyzed chemoselective reduction of enimines to N-Allylic amines via hydrosilylation0 aIroncatalyzed chemoselective reduction of enimines to NAllylic a cMAY0 v143 a

Chemoselective hydrosilylation of unsaturated imines is challenging as the two double bonds compete for the reaction. Here in, we report an iron-catalyzed chemoselective hydrosilylation of enimines leading to the generation of allyl amines in the presence of phosphine ligand. A low-valent Fe(0) complex [(BDA)Fe(CO)3] catalyzed the hydrosilylation of enimine at room temperature and exhibited broad substrate scope including a variety of enimine (cinnamylimine, allylimine) and ketimine. Mechanistic investigations revealed that the reaction proceeds through an oxidative addition of the silane compound, leading to the formation of an iron hydride intermediate. Subsequently, a two-electron pathway facilitates the hydrosilylation of the enimine substrate. This has been supported by preparing a well-defined Fe(II)-silane complex and using it as a catalyst control. Based on experimental and computational investigations, a plausible Chalk-Harrod-type mechanism is proposed.

10aCinnamyl amine10aImine hydrosilylation10airon catalysis10aIron hydride10aPhosphine1 aTewari, Tanuja1 aShaikh, Maulali, H.1 aSharma, Himanshu1 aVanka, Kumar1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/iron-catalyzed-chemoselective-reduction-enimines-n-allylic-amines-hydrosilylation01926nas a2200205 4500008004100000022001400041245006600055210006600121260000800187490000800195520125700203653002701460653002801487653001701515100002601532700001801558700002401576700002401600856009601624 2025 eng d a1022-135200aRenewable and degradable polyoxalates derived from castor oil0 aRenewable and degradable polyoxalates derived from castor oil cSEP0 v2263 a

Renewable feedstocks pave the way to reduce the demand for petroleum-derived chemicals. Castor oil is one such plant-based raw material that can be used to synthesize chemicals and materials with diverse applications. Herein, we report the synthesis of a novel monomer, 18-methoxy-18-oxooctadec-9-en-7-yl methyl oxalate (3), from castor oil-derived ricinoleic acid. The identity of the monomer 3 has been unambiguously ascertained using 1-2D NMR spectroscopic analysis. Monomer 3 was then subjected to condensation polymerization with potentially bio-renewable long-chain aliphatic diols to yield degradable linear polyoxalates having molecular weights in the range of 8000-22,000 g/mol. The polymerization reactions were performed using pTSA and [Sn(Oct)2] as catalysts, and the polymerization conditions were optimized. The structure of the polymer was confirmed by 1-2D NMR spectroscopy, IR spectroscopy, and GPC analysis. The thermal characterizations of the polyoxalates were carried out by DSC and TGA analysis. The polyoxalates were found to degrade in acidic media. These renewable polyoxalates were further reacted with thiols by ``thiol-ene'' click reaction to produce a cross-linked rubbery polymer, which retained degradability.

10acastor oil derivatives10ahydrolytic degradations10apolyoxalates1 aMenon, Abhijith, Hari1 aJoseph, Seena1 aShaikh, Maulali, H.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/renewable-and-degradable-polyoxalates-derived-castor-oil02178nas a2200217 4500008004100000022001400041245009500055210006900150260000900219490000700228520138400235653003201619653004101651653001901692653003601711653002401747100001901771700002401790700002401814856012201838 2025 eng d a1867-388000aRh-Catalyzed Asymmetric Hydroformylation: The Case of Substituted and Heterocyclic Olefins0 aRhCatalyzed Asymmetric Hydroformylation The Case of Substituted  cNOV 0 v173 a

Asymmetric hydroformylation (AHF) of prochiral alkenes is an efficient way to synthesize optically active aldehydes, which are versatile chiral building blocks for pharmaceuticals, agrochemicals, and other fine chemicals. The purpose of this review is to take stock of developments in the last decade and shed light on the understanding of the field of AHF. So far, most of the literature methods focused on the use of Rh-based catalysts, due to high catalytic activity and excellent chemoselectivity for the aldehydes. Several chiral phosphorus ligands have been successfully developed for Rh-catalyzed AHF reactions. This review examines the role of the substrate/olefins in AHF. Several different types of ``mono-substituted'' terminal olefins (functionalized/nonfunctionalized) with a variety of chiral ligands have been investigated, which show high activity and excellent ee of up to 99%. The AHF of ``di-substituted'' and ``tri-substituted'' olefins is rarely reported. This review summarizes the evolution of chiral ligands for AHF. It discusses the progress made in desymmetrizing hydroformylation. In addition, it highlights important developments in AHF carried out with and without syngas. These advances span a wide variety of alkenes. Additionally, the review offers future approaches in the field of AHF for the synthesis of optically active aldehydes.

10aAsymmetric hydroformylation10aAsymmetric transfer hydroformylation10aChiral ligands10aDesymmetrizing hydroformylation10aSubstituted alkenes1 aTewari, Tanuja1 aKhopade, Kishor, V.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/rh-catalyzed-asymmetric-hydroformylation-case-substituted-and-heterocyclic-olefins02171nas a2200241 4500008004100000245011900041210006900160260000800229490000700237520131600244653001901560653002601579653001401605653001401619653001801633100002101651700002401672700002601696700003101722700002401753700002001777856013201797 2025 eng d00aRuthenium-catalyzed deconstruction of polyolefins: a strategy to up-cycle waste polyethylene to value-added alkene0 aRutheniumcatalyzed deconstruction of polyolefins a strategy to u cAPR0 v643 a

Synthesis of value-added products from post-consumer waste polyolefins is fascinating as well as challenging. Here we report ruthenium-catalyzed up-cycling of the polyethylene to long-chain alkene derivatives. The developed methodology mainly involves two steps i.e., dehydrogenation of polyethylene through hydrogen atom transfer and its metathesis using the HG-II catalyst. The dehydrogenation of polyethylene using ruthenium catalysis derived up to 3.38 %, of double bonds; with 90 % of the recovered polyolefin material. The obtained unsaturated polyethylene was subjected to cross-metathesis with ethylene using HG-II catalytic system. This resulted in the synthesis of predominantly dodecene (C12) derivatives, with 58 % selectivity, along with other derivatives of varying chain lengths. The overall reaction produced terminal and internal olefins in the ratio 1:0.8 respectively. The dehydrogenation of polyethylene and its deconstruction was confirmed by NMR spectroscopy, Gel Permeation Chromatography (GPC) and Differential Scanning Calorimetry (DSC). The origin of C12 selectivity has been demonstrated by control experiments. The scope of the methodology was extended to post-consumer waste polyethylene which gave high conversion to value-added dodecene derivatives as a major product.

10aDeconstruction10aHomogeneous catalysis10aruthenium10aUpcycling10aWaste plastic1 aPadhi, Ganeshdev1 aKhopade, Kishor, V.1 aMoyilla, Nageswararao1 aRangappa, Raghavendrakumar1 aChikkali, Samir, H.1 aBarsu, Nagaraju uhttps://library.ncl.res.in/content/ruthenium-catalyzed-deconstruction-polyolefins-strategy-cycle-waste-polyethylene-value-added02521nas a2200265 4500008004100000022001400041245007300055210006900128260000800197300001400205490000600219520170800225653000901933653002001942653001801962653001701980653001901997100001802016700002002034700001802054700002702072700002402099700002702123856010502150 2025 eng d a2637-610500aThermal properties of polyethylene-grafted sheetlike silsesquioxanes0 aThermal properties of polyethylenegrafted sheetlike silsesquioxa cMAR a4290-43000 v73 a

Polyethylene-grafted layered silsesquioxanes, termed polyethylene-clays (PEC), are nanocomposites comprising polyethylene chains tethered to inorganic sheets with a phyllosilicate-like structure. Here, we report that these nanocomposites show two-stage crystallization on cooling, qualitatively different from previous reports on polyethylene nanocomposites. We employ differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS) to study the melting and crystallization of PEC. End tethering of the polyethylene chains to a nanosheet strongly influences the manner in which PEC crystallizes from the melt on cooling. PEC exhibits two-step crystallization, characterized by a sharp high-temperature exotherm, followed by a broader exotherm at lower temperatures, in contrast to a single sharp exotherm for neat polyethylene. SAXS indicates that lamellar stacks form at high temperatures and that the low-temperature exotherm corresponds to the formation of additional lamellae and their insertion within these stacks. PEC exhibits lower peak melting temperature, lower crystallinity, and a wider melting range relative to polyethylene. We show that the progress of crystallization of PEC is determined by its ultraslow relaxation dynamics. In contrast, PEC in xylene solution exhibits a significantly shorter relaxation time than the melt PEC. Such systems exhibited a single exotherm on cooling and SAXS structure factor peaks with peak positions in a ratio of 1:2. We hypothesize that the high melt viscosity inhibits the crystallization-induced decrease in the specific volume of PEC, resulting in tensile internal stresses that determine the observed thermal behavior.

10aclay10aCrystallization10aNanocomposite10aPolyethylene10asilsesquioxane1 aSharma, Vivek1 aPaulbudhe, Uday1 aGupta, Poonam1 aZalte, Akshat, Shirish1 aChikkali, Samir, H.1 aKumaraswamy, Guruswamy uhttps://library.ncl.res.in/content/thermal-properties-polyethylene-grafted-sheetlike-silsesquioxanes01640nas a2200229 4500008004100000022001400041245012500055210006900180260000900249300001100258490000700269520081400276653002901090653002601119653001801145653002001163653002401183100002701207700002401234700002401258856012801282 2026 eng d a2365-654900aDirect synthesis of phosphine-phosphite ligand and its implication in asymmetric hydrogenation of functionalized olefins0 aDirect synthesis of phosphinephosphite ligand and its implicatio cFEB  ae075480 v113 a

Phosphine-phosphite (P-OP) ligands constitute a privileged class of chiral ligands in asymmetric catalysis owing to their modular structures and tunable steric and electronic properties. Herein, we report a direct, one-pot, synthesis of a new flexible P-OP ligand (L) derived from BINOL-PCl and its in situ complexation with rhodium (Rh) for catalytic evaluation. The resulting Rh/L system efficiently hydrogenates a diverse library of 19 functionalized olefins under mild conditions, delivering moderate to excellent enantioselectivities, with ee values reaching up to 99%. Several of the hydrogenated products correspond to valuable chiral building blocks relevant to pharmaceutical synthesis, underscoring the practical utility of flexible P-OP ligand architectures in asymmetric hydrogenation.

10aasymmetric hydrogenation10afunctionalized alkene10aligand design10ametal catalyzed10aphosphine-phosphite1 aChandanshive, Amol, C.1 aKhopade, Kishor, V.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/direct-synthesis-phosphine-phosphite-ligand-and-its-implication-asymmetric-hydrogenation01957nas a2200205 4500008004100000022001400041245008000055210006900135260000800204490000700212520126000219653002101479653002301500653002301523653002401546653001801570100002701588700002401615856011201639 2026 eng d a1861-472800aP-chiral organophosphorus compounds: synthesis, mechanism, and applications0 aPchiral organophosphorus compounds synthesis mechanism and appli cJAN0 v213 a

The enantioselective synthesis of P-stereogenic compounds has emerged as a central focus in modern asymmetric catalysis, driven by their pivotal roles as ligands (Ls), organocatalysts, and bioactive molecules. Over the past decade, significant advances have been made in developing catalytic strategies that enable precise control over phosphorus stereochemistry, expanding both the structural diversity and synthetic utility of these scaffolds. This review highlights recent progress in two key areas: direct P-C bond formation and desymmetrization. P-C bond-forming approaches include cross-coupling reactions of secondary phosphines or their oxides with aryl, alkyl, or benzyl halides, as well as hydrophosphination of alkenes and alkynes. Desymmetrization strategies encompass nucleophilic substitution at P(V) centers, cyclization, C-H activation (CHA), phenolic -OH activation, and P-O alkylation/arylation. Mechanistic insights into these transformations have been discussed, along with the derivatization of P-chiral products and their applications in catalysis, L design, and bioactive molecule synthesis. This comprehensive overview shall serve as a valuable resource for researchers working in asymmetric organophosphorus chemistry.

10adesymmetrization10aHydrophosphination10aP-C cross coupling10aP-chiral phosphines10aphosphination1 aChandanshive, Amol, C.1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/p-chiral-organophosphorus-compounds-synthesis-mechanism-and-applications