01407nas a2200181 4500008004100000022001400041245011700055210006900172260007100241300001400312490000800326520067900334100002001013700002301033700002101056700001701077856013101094 2012 eng d a1520-610600aExploring the potential of doped zero-dimensional cages for proton transfer in fuel cells: a computational study0 aExploring the potential of doped zerodimensional cages for proto a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAUG a9803-98110 v1163 a

Calculations with density functional theory (DFT) and MP2 have been done to investigate the potential of recently synthesized durable zero-dimensional (OD) nitrogen-based cage structures to perform as efficient proton-exchange membranes (PEMs) in fuel cells. Our calculations suggest that the hydrogenated 0-D cages, in combination with hydrogen-bonding 1,2,3- and 1,2,4-triazole molecules, would perform as highly efficient PEMs. The results are important in the context of the need for efficient PEMs for fuel cells, especially at higher temperatures (greater than 120 degrees C) where conventional water-based PEMs such as Nafion have been found to be ineffective.

1 aMane, Manoj, V.1 aVenkatnathan, Arun1 aGhatak, Kamalika1 aVanka, Kumar uhttps://library.ncl.res.in/content/exploring-potential-doped-zero-dimensional-cages-proton-transfer-fuel-cells-computational-001682nas a2200157 4500008004100000022001400041245015400055210006900209260011000278300001600388490000700404520095400411100001601365700001701381856012601398 2013 eng d a1463-907600aExploring the effectiveness of different Lewis pair combinations in caged structures for the catalysis of ammonia borane dehydrogenation: a DFT study0 aExploring the effectiveness of different Lewis pair combinations aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a20857-208670 v153 a

Zero dimensional cage structures containing four phenyl rings separated by imine linkers have recently been synthesized. In the current work, through a computational investigation using density functional theory (DFT), we demonstrate that modifying such cages by replacing the 2, 4, 6 carbon atoms in the phenyl rings to yield new rings, as well as replacing the imine moiety in the linker by other electronegative atoms, can yield interesting new cages that can be reactive in catalysing reactions such as the dehydrogenation of ammonia borane-an important reaction in hydrogen storage research. Specifically, it is predicted that phosphorus-nitrogen pairs (phosphorus in the 2, 4, 6 positions in the ring, nitrogen in the linker position), germanium-nitrogen and germanium-phosphorus pair combinations would lead to effective Lewis pairs that can work in tandem to dehydrogenate ammonia borane efficiently under room temperature conditions.

1 aPal, Amrita1 aVanka, Kumar uhttps://library.ncl.res.in/content/exploring-effectiveness-different-lewis-pair-combinations-caged-structures-catalysis-001843nas a2200229 4500008004100000022001400041245009900055210006900154260007500223300001400298490000600312520101500318653001501333653001301348653003601361653002201397653001301419100001901432700002701451700001701478856011801495 2016 eng d a1867-388000aEffect of donors on the activation mechanism in ziegler-natta catalysis: a computational study0 aEffect of donors on the activation mechanism in zieglernatta cat aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcMAY a1809-18180 v83 a

Full quantum chemical calculations, using density functional theory (DFT), have been conducted to explain the effect of donors on the ``activation mechanism'' in the Ziegler-Natta (Z-N) catalyst system. In the activation mechanism, the inactive (TiCl4)-Cl-IV catalyst converts into the active (TiCl2Et)-Cl-III catalyst with the help of the AlEt3 present in the system. The donors that have been considered in this study are: ethyl benzoate (eb), two representative diether cases, a phthalate donor, and a silyl ester donor. The results indicate that eb and the diether donor cases donor have a negative effect on the barriers for the activation mechanism. However, the eb donor can be displaced from the MgCl2 surface by AlEt3, which matches experimental observations. For the phthalate, silyl ester and TiCl3-OC4H8Cl cases, the results indicate that a significant induction period would be present in Z-N systems employing such donors or having such a catalytic center, before catalysis could commence.

10aAlkylation10aaluminum10aDensity functional calculations10asurface chemistry10atitanium1 aKumawat, Jugal1 aGupta, Virendra, Kumar1 aVanka, Kumar uhttps://library.ncl.res.in/content/effect-donors-activation-mechanism-ziegler-natta-catalysis-computational-study01621nas a2200181 4500008004100000022001400041245018100055210006900236260011000305300001600415490000600431520079500437100002401232700002501256700001501281700001701296856012601313 2016 eng d a2046-206900aExploration of the diastereoselectivity in an unusual Grignard reaction and its application towards the synthesis of styryl lactones 7-epi-(+)-goniodiol and 8-epi-(-)-goniodiol0 aExploration of the diastereoselectivity in an unusual Grignard r aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAY a50721-507250 v63 a

An unusual diastereoselective Grignard reaction is explored, where the Grignard reagents are derived from 1,n-dihaloalkanes. A steric bias due to the presence of a quaternary centre adjacent to the acetonide ester at the benzylic position is responsible for the formation of an intramolecularly reduced product in almost quantitative yield. This steric hindrance is responsible for the diastereoselectivity observed with a variety of aromatic as well as aliphatic esters. The unusual Grignard reaction furnishes long chain secondary alcohols possessing a terminal olefin, which are synthetically important intermediates. As an application of this method, the diastereoselective synthesis of styryl lactones viz. 7-epi-(+)-goniodiol (29) and 8-epi(-)-goniodiol (30) has been achieved.

1 aChavan, Subhash, P.1 aKhatod, Harshali, S.1 aDas, Tamal1 aVanka, Kumar uhttps://library.ncl.res.in/content/exploration-diastereoselectivity-unusual-grignard-reaction-and-its-application-towards01790nas a2200229 4500008004100000022001400041245009600055210006900151260006900220300001000289490000800299520094800307653004901255653002101304653001601325653001201341100002301353700002501376700002101401700001701422856012101439 2016 eng d a0022-328X00aExploring activity differences between the hydroformylation catalysts: Insights from theory0 aExploring activity differences between the hydroformylation cata aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcJAN a30-410 v8013 a

Hydroformylation catalysis is the most important homogeneous catalysis process of the current day. The current computational investigation aims to understand the nature of the hydroformylation process when monodentate ligands are employed. The complete catalytic cycle for different monodentate ligands bound to the rhodium center has been studied with full quantum chemical calculations, with density functional theory (DFT). To the best of our knowledge, this is the first systematic investigation of the relative free energy surfaces for mono-coordinate monodentate and bi-coordinated monodentate ligands in hydroformylation catalysis. The results indicate that the barriers are lower for the mono-coordinate monodentate species in comparison to the bi-coordinate monodentate, for all the ligand cases studied, indicating higher activity for the mono-coordinate monodentate active species. (C) 2015 Elsevier B.V. All rights reserved.

10aDensity functional theory (DFT) calculations10aHydroformylation10aMonodentate10aRhodium1 aDangat, Yuvraj, B.1 aRizvi, Masood, Ahmad1 aPandey, Pippalad1 aVanka, Kumar uhttps://library.ncl.res.in/content/exploring-activity-differences-between-hydroformylation-catalysts-insights-theory01550nas a2200157 4500008004100000022001400041245006900055210006800124260011000192300001400302490000700316520093800323100002301261700001701284856009101301 2016 eng d a1477-922600aExploring the reducing role of boron: added insights from theory0 aExploring the reducing role of boron added insights from theory aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcNOV a5978-59880 v453 a

Carbon-carbon coupling in CO molecules is a challenging proposition, and very few main group complexes have been shown to effect this process. A recently reported triply bonded diboryne system (1) is notable for coupling four CO molecules to produce a (bis) boralactone species. The current full quantum chemical computational investigation with density functional theory (DFT) provides important insights into the nature of the CO coupling process by triply bonded diboryne systems. The complete reaction pathway leading to the formation of the (bis) boralactone has been determined. Factors that make this system so successful in coupling CO groups have been elucidated, and pertinent issues, such as why the coupling process stops after four CO additions, have been explored. Also, importantly, insights have been gained through the natural bond orbital (NBO) analysis into how the back-donation from diboryne activates CO.

1 aDangat, Yuvraj, B.1 aVanka, Kumar uhttps://library.ncl.res.in/content/exploring-reducing-role-boron-added-insights-theory02085nas a2200253 4500008004100000022001400041245013600055210006900191260000900260300001400269490000700283520119800290653001401488653001501502653002001517653001901537653003601556100002201592700001901614700002501633700001701658700002401675856013201699 2017 eng d a0947-653900aElectronic control on linear versus branched alkylation of 2-/3-aroylbenzofurans with acrylates: combined DFT and synthetic studies0 aElectronic control on linear versus branched alkylation of 23aro cJUN  a7570-75810 v233 a

Investigations on the factors that govern unusual branched alkylation of 2-aroylbenzofurans with acrylates by Ru-catalyzed carbonyl-directed C-H activation has been carried out by calculating the kinetics associated with the two key steps-the coordination of the acrylate with the intermediate ruthenacycle and the subsequent migratory insertion reaction-studied with the help of DFT calculations. Eight possible orientations for each mode of alkylation have been considered for the calculations. From these calculations, it has been understood that there is a synergistic operation of the steric and electronic effects favoring the branched alkylation. Further DFT investigations on the alkylation of the isomeric 3-aroylbenzofurans indicated a preference for the linear alkylation and this has been verified experimentally. Overall, the observed/calculated complementary selectivity in the alkylation of 2-/3-aroylbenzofurans with acrylates reveals that the substrate-dependent charge distribution of the Ru-C bond in the intermediate ruthenacycle is an important determining factor and thus the current work opens up a new domain of substrate design for controlling regioselectivity.

10aacrylates10aAlkylation10aaroylbenzofuran10aC-H activation10aDensity functional calculations1 aSrinivas, Kolluru1 aDangat, Yuvraj1 aKommagalla, Yadagiri1 aVanka, Kumar1 aRamana, Chepuri, V. uhttps://library.ncl.res.in/content/electronic-control-linear-versus-branched-alkylation-2-3-aroylbenzofurans-acrylates-combined01603nas a2200145 4500008004100000245012000041210006900161260000800230300001400238490000600252520103300258100002301291700001701314856012601331 2017 eng d00aExploiting directional long range secondary forces for regulating electrostatics dominated noncovalent interactions0 aExploiting directional long range secondary forces for regulatin cJAN a1378-13900 v83 a

It has been well established that long range secondary electrostatic interactions (SEIs) have a significant effect on the stability of supramolecular complexes. However, general rules for exploiting SEIs in the rational design of diverse supramolecular complexes have been difficult to obtain. In this work, we outline a quantum chemical approach for understanding the strength of electrostatic interactions. This approach is seen to provide excellent correlation between the electrostatic force and the binding energy between two partners in hydrogen-bonded complexes, as well as that between two ions in ion-pair complexes. Furthermore, we illustrate how the understanding of the binding allows for the rational design of new complexes where the association constant between the two partners can be increased or decreased, as desired, by several orders of magnitude. Hence, the current work showcases a general, simple and powerful method of understanding and exploiting long range secondary electrostatic interactions.

1 aTiwari, Mrityunjay1 aVanka, Kumar uhttps://library.ncl.res.in/content/exploiting-directional-long-range-secondary-forces-regulating-electrostatics-dominated00817nas a2200157 4500008004100000245012400041210006900165260000800234490000700242520022400249100001700473700001500490700001700505700001900522856011800541 2018 eng d00aEasily accessible lithium compound catalyzed mild and facile hydroboration and cyanosilylation of aldehydes and ketones0 aEasily accessible lithium compound catalyzed mild and facile hyd cAPR0 v543 aSimple and readily accessible lithium compounds such as 2,6-ditertbutyl phenolate lithium (1a), 1,1' dilithioferrocene (1b) and nacnac lithium (1c) are found to be efficient single site catalysts for hydroboration of...1 aBisai, Milan1 aDas, Tamal1 aVanka, Kumar1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/easily-accessible-lithium-compound-catalyzed-mild-and-facile-hydroboration-and01926nas a2200157 4500008004100000022001400041245016900055210006900224260000900293300001400302490000800316520128400324100001801608700001701626856012501643 2020 eng d a1089-563900aEffect of solvent-substrate noncovalent interactions on the diastereoselectivity in the intramolecular carbonyl-ene and the staudinger [2+2] cycloaddition reactions0 aEffect of solventsubstrate noncovalent interactions on the diast cOCT  a8019-80280 v1243 a

Noncovalent interactions (NCIs) have been identified as important contributing factors for determining selectivity in organic transformations. However, cases where NCIs between solvents and substrates are responsible for a major extent for determining selectivity are rare. The current computational study with density functional theory identifies two important transformations where this is the case: the intramolecular carbonyl-ene reaction and the Staudinger [2 + 2] cycloaddition reaction. In both cases, the role of explicit solvent molecules interacting non-covalently with the substrate has been taken into account. Calculations indicate that the diastereomeric ratio would be 95.0:5.0 for the formation of tricyclic tetrahydrofuran diastereomers via the intramolecular carbonyl-ene reaction and 94.0:6.0 for the formation of the triflone diastereomers via the Staudinger [2 + 2] cycloaddition reaction, which corroborates with the experiment. Interestingly, in both the cases, the calculations indicate that noninclusion of explicit solvent molecules would lead to only a small difference between the competing transition states, which leads to the conclusion that solvent-substrate NCIs are the major cause for diastereoselectivity in both the cases considered.

1 aJain, Shailja1 aVanka, Kumar uhttps://library.ncl.res.in/content/effect-solvent-substrate-noncovalent-interactions-diastereoselectivity-intramolecular01155nas a2200193 4500008004100000022001400041245012800055210006900183260000800252300001400260490000700274520044600281100002600727700002500753700001700778700001700795700002600812856012300838 2021 eng d a1477-052000aEasy and practical approach to access multifunctional cylcopentadiene- and cyclopentene-spirooxindoles via [3+2] annulation0 aEasy and practical approach to access multifunctional cylcopenta cMAY a4338-43450 v193 a

A highly regioselective [3 + 2] annulation of Morita-Baylis-Hillman (MBH) carbonates of isatin with aurone/thioaurone is developed. Spiroheterocycles such as spirooxindole cyclopentadiene and spirooxindole fused hydroxy cyclopentene derivatives are constructed in one pot by exploring the reactivity of Lewis bases. Combined experimental and density functional theory (DFT) calculations offered an insight into the reaction mechanism.

1 aWarghude, Prakash, K.1 aSabale, Abhijeet, S.1 aDixit, Ruchi1 aVanka, Kumar1 aBhat, Ramakrishna, G. uhttps://library.ncl.res.in/content/easy-and-practical-approach-access-multifunctional-cylcopentadiene-and-cyclopentene02274nas a2200205 4500008004100000022001400041245012100055210006900176260000900245300000800254490000700262520153100269100002301800700002501823700002101848700003001869700001701899700002201916856013001938 2022 eng d a0039-788100aEnantioselective Cu(I)-catalyzed borylative cyclization of enone-tethered cyclohexadienones and mechanistic insights0 aEnantioselective CuIcatalyzed borylative cyclization of enonetet cFEB  a8540 v133 a

Rapidly building molecular structures with both elements of complexity and flexibility is a key goal of organic synthesis. Here the authors show a tandem copper-catalyzed beta-borylation/Michael addition on prochiral enone-tethered 2,5-cyclohexadienones, to generate bicyclic borylated products in high yield and enantioselectivity. The catalytic asymmetric borylation of conjugated carbonyls followed by stereoselective intramolecular cascade cyclizations with in situ generated chiral enolates are extremely rare. Herein, we report the enantioselective Cu(I)-catalyzed beta-borylation/Michael addition on prochiral enone-tethered 2,5-cyclohexadienones. This asymmetric desymmetrization strategy has a broad range of substrate scope to generate densely functionalized bicyclic enones bearing four contiguous stereocenters with excellent yield, enantioselectivity, and diastereoselectivity. One-pot borylation/cyclization/oxidation via the sequential addition of sodium perborate reagent affords the corresponding alcohols without affecting yield and enantioselectivity. The synthetic potential of this reaction is explored through gram-scale reactions and further chemoselective transformations on products. DFT calculations explain the requirement of the base in an equimolar ratio in the reaction, as it leads to the formation of a lithium-enolate complex to undergo C-C bond formation via a chair-like transition state, with a barrier that is 22.5 kcal/mol more favourable than that of the copper-enolate complex.

1 aJadhav, Sandip, B.1 aDash, Soumya, Ranjan1 aMaurya, Sundaram1 aNanubolu, Jagadeesh, Babu1 aVanka, Kumar1 aChegondi, Rambabu uhttps://library.ncl.res.in/content/enantioselective-cui-catalyzed-borylative-cyclization-enone-tethered-cyclohexadienones-and01858nas a2200265 4500008004100000022001400041245009300055210006900148260000800217300001500225490000700240520100900247653002401256653002401280653000801304653002701312653001801339100001701357700002501374700001601399700001701415700001701432700001901449856012401468 2023 eng d a2192-650600aEnhancing diradical character of chichibabin's hydrocarbon through fluoride substitution0 aEnhancing diradical character of chichibabins hydrocarbon throug cAUG ae2023002730 v883 a

In this work, 5-SIDipp [SIDipp=1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene] (1) derived Chichibabin's hydrocarbon with an octafluorobiphenylene spacer (3) has been reported. The addition of two equivalents of 5-SIDipp with decafluorobiphenyl in presence of BF3 gives the double C-F bond activated imidazolium salt with two tetrafluoroborate anions, 2. Further reduction of 2 gives the fluorine substituted 5-SIDipp based Chichibabin's hydrocarbon, 3. Quantum chemical calculations suggested a singlet state of 3 with a singlet-triplet energy gap (?ES-T) of 3.7 kcal mol(-1), which is substantially lower with respect to the hydrogen substituted NHC-based Chichibabin's hydrocarbons (10.7 kcal mol(-1), B3LYP). As a result, the diradical character (y) of 3 (y=0.62) is also noticeably higher than the hydrogen substituted CHs (y=0.41-0.43). The ?ES-T was found to be higher in CASSCF (22.24 kcal mol(-1)) and CASPT2 (11.17 kcal mol(-1)) for 3 and the diradical character (d) is 44.6 %.

10aC-F Bond Activation10aChichibabin & PRIME10aDFT10aN-Heterocyclic carbene10as Hydrocarbon1 aKundu, Gargi1 aDash, Soumya, Ranjan1 aKumar, Ravi1 aVanka, Kumar1 aGhosh, Aryya1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/enhancing-diradical-character-chichibabins-hydrocarbon-through-fluoride-substitution03030nas a2200205 4500008004100000022001400041245018300055210006900238260000800307300001600315490000600331520222200337100001802559700002702577700001702604700001702621700003002638700002702668856012902695 2024 eng d a2470-134300aEffect of position of donor units and alkyl groups on dye-sensitized solar cell device performance: indoline-aniline donor-based visible light active unsymmetrical squaraine dyes0 aEffect of position of donor units and alkyl groups on dyesensiti cMAR a16429-164420 v93 a

Indoline (In) and aniline (An) donor-based visible light active unsymmetrical squaraine (SQ) dyes were synthesized for dye-sensitized solar cells (DSSCs), where the position of An and In units was changed with respect to the anchoring group (carboxylic acid) to have In-SQ-An-CO2H and An-SQ-In-CO2H sensitizers, AS1-AS5. Linear or branched alkyl groups were functionalized with the N atom of either In or An units to control the aggregation of the dyes on TiO2. AS1-AS5 exhibit an isomeric pi-framework where the squaric acid unit is placed in the middle, where AS2 and AS5 dyes possess the anchoring group connected with the An donor, and AS1, AS3, and AS4 dyes having the anchoring group connected with the In donor. Hence, the conjugation between the middle squaric acid acceptor unit and the anchoring -CO2H group is short for AS2, AS5, and AK2 and longer for AS1, AS3, and AS4 dyes. AS dyes showed absorption between 501 and 535 nm with extinction coefficients of 1.46-1.61 x 10(5) M-1 cm(-1). Further, the isomeric pi-framework of An-SQ-In-CO2H and In-SQ-An-CO2H exhibited by means of changing the position of In and An units a bathochromic shift in the absorption properties of AS2 and AS5 compared to the AS1, AS3, and AS4 dyes. The DSSC device fabricated with the dyes contains short acceptor-anchoring group distance (AS2 and AS5) showed high photovoltaic performances compared to the dyes having longer distance (AS1, AS3, and AS4) with the iodolyte (I-/I-3(-)) electrolyte. DSSC device efficiencies of 5.49, 6.34, 6.16, and 5.57% have been achieved for AS1, AS2, AS3, and AS4 dyes, respectively; without chenodeoxycholic acid (CDCA), small changes have been observed in the device performance of the AS dyes with CDCA. Significant changes have been noted in the DSSC parameters (open-circuit voltage V-OC, short-circuit current J(SC), fill factor ff, and efficiency eta) for the AS5 dye while sensitized with CDCA and showed highest DSSC efficiency of 8.01% in the AS dye series. This study revealed the potential of shorter SQ acceptor-anchoring group distance over the longer one and the importance of alkyl groups on the overall DSSC device performance for the unsymmetrical squaraine dyes.

1 aSingh, Amrita1 aSingh, Ambarish, Kumar1 aDixit, Ruchi1 aVanka, Kumar1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/effect-position-donor-units-and-alkyl-groups-dye-sensitized-solar-cell-device-performance02184nas a2200205 4500008004100000022001400041245014300055210007000198260000800268490000700276520142000283653002001703653002601723653003001749653001501779653000901794100002501803700001701828856013301845 2024 eng d a1439-423500aExploring unconventional σ-hole interactions: computational insights into the interaction of XeO3 with non-aromatic coordinating solvents0 aExploring unconventional σhole interactions computational insigh cMAR0 v253 a

In order to control the explosiveness and shock sensitivity of XeO3, we have investigated its plausible interaction with various non-aromatic coordinating solvents, serving as potential Lewis base donors, through density functional theory (DFT) calculations. Out of twenty six such solvents, the top ten were thus identified and then thoroughly examined by employing various computational tools such as the mapping of the electrostatic potential surface (MESP), Wiberg bond indices (WBIs), non-covalent interaction (NCI) plots, Bader's theory of atoms-in-molecules (AIM), natural bond orbital (NBO) analysis, and the energy decomposition analysis (EDA). The amphoteric nature of XeO3 was also explored by investigating the extent of back donation from the lone pair of Xe to the antibonding orbital of the donating atom/group of the solvent molecules. The C-H & mldr;O interactions were also found to be a contributing factor in the stabilization of these adducts. Although these aerogen-bonding interactions were found to be predominantly electrostatic, significant contributions from the orbital contributions, as well as dispersion interactions, were observed. The top three non-aromatic solvents (among the twenty six studied) which form the strongest adducts with XeO3 are proposed to be hexamethylphosphoramide (HMPA), N,N `-dimethylpropyleneurea (DMPU) and tetramethylethylenediamine (TMEDA).

10aAerogen bonding10aNon-Aromatic Solvents10anon-covalent interactions10aSigma-hole10aXeO31 aDash, Soumya, Ranjan1 aVanka, Kumar uhttps://library.ncl.res.in/content/exploring-unconventional-%CF%83-hole-interactions-computational-insights-interaction-xeo3-non