01704nas a2200193 4500008004100000245019700041210006900238260000800307300001800315490000700333520090500340100002401245700001901269700002501288700002501313700002401338700001901362856012901381 2011 eng d00aPhotocatalytic splitting of CS2 to a carbon-sulfur polymer and S8 catalyzed by a bimetallic ruthenium(II) compound with a tertiary amine binding site - towards photocatalytic splitting of CO2?0 aPhotocatalytic splitting of CS2 to a carbonsulfur polymer and S8 cOCT a11273–112750 v503 a

The catalytic photocleavage of CS2 to S8 and a (CxSy)n polymer with visible light using a dinuclear ruthenium(II) compound with a bipyridine units for photoactivity and a vicinal tertiary amine binding site for CS2 activation was studied. The catalyst was characterized by X-ray diffraction, 1H NMR, and 13C NMR, ESI-MS and elemental analysis. CS2 photocleavage was significant (240 turnovers, 20 h) to yield isolable S8 and a (CxSy)n polymer. A mononuclear catalyst or one without an amine binding site showed significantly less activity. XPS of the (CxSy)n polymer showed a carbon/sulfur ratio ∼1.5–1.6 indicating that in part both C–S bonds of CS2 had been cleaved. Catalyst was also included within the polymer. The absence of peaks in the 1H NMR verified the (CxSy)n nature of the polymer, while 13C NMR and IR indicated that the polymer had multiple types of C–S and C–C bonds.

1 aLivanov, Konstantin1 aMadhu, Vedichi1 aBalaraman, Ekambaram1 aShimon, Linda, J. W.1 aDiskin-Posner, Yael1 aNeumann, Ronny uhttp://library.ncl.res.in/content/photocatalytic-splitting-cs2-carbon-sulfur-polymer-and-s8-catalyzed-bimetallic-rutheniumii02342nas a2200193 4500008004100000245016200041210006900203260000800272300001600280490000700296520155600303100003301859700002501892700002401917700002001941700002501961700002001986856014202006 2013 eng d00aPNN-Ru pincer complexes based on phosphinated 2,2’-dipyridinemethane- and 2,2’-oxobispyridine. metal-ligand cooperation in cyclometallation and catalysis0 aPNNRu pincer complexes based on phosphinated 22 dipyridinemethan cMAY a2973–29820 v323 a

The synthesis of novel PNN ruthenium pincer complexes based on 2,2′-dipyridinemethane phosphine derivatives, as well as on 2,2′-oxobispyridine phosphine ligands, and their reactivity toward dearomatization and cyclometalation are described. The dearomatized compounds 7a,b undergo cyclometalation to yield complexes 8a,b. In order for cyclometalation to proceed, the coordination sphere around the Ru center has to rearrange, and this depends on the flexibility of the system, showing that the cyclometalation is qualitatively faster in the case of the dimethyl derivative 7a than in the case of the spyrocyclopentyl derivative 7b. The cyclometalation occurs diastereoselectively and leads to only one diastereomer of the cyclometalated compounds. In the case of the 2,2′-oxobispyridine complex 6c, the dearomatized complex was too unstable to be isolated; however it was possible to isolate and characterize a stable dicarbonyl-dearomatized ruthenium(II) complex, 9c, when the deprotonation was performed under a CO atmosphere. Dearomatization of 6a under CO also led to dicarbonyl-dearomatized ruthenium(II) complex 9a, which slowly rearranged into the dicarbonyl-aromatized ruthenium(0) complex 10a. These complexes were tested in catalytic alcohol–amine coupling, esterification of primary alcohols, and hydrogenation of secondary amides. Moderate activity was observed in hydrogenation of amides to alcohols and amines and low activity in the other transformations, owing mainly to the formation of stable cyclometalated compounds.

1 aBarrios-Francisco, Rigoberto1 aBalaraman, Ekambaram1 aDiskin-Posner, Yael1 aLeitus, Gregory1 aShimon, Linda, J. W.1 aMilstein, David uhttp://library.ncl.res.in/content/pnn-ru-pincer-complexes-based-phosphinated-22%E2%80%99-dipyridinemethane-and-22%E2%80%99-oxobispyridine02008nas a2200217 4500008004100000245017300041210006900214260000800283300001600291490000600307520117200313100002101485700002801506700001701534700002001551700002401571700002101595700002501616700002001641856012901661 2017 eng d00aPredesigned metal-anchored building block for in situ generation of Pd nanoparticles in porous covalent organic framework: application in heterogeneous tandem catalysis0 aPredesigned metalanchored building block for in situ generation  cAPR a13785-137920 v93 aThe development of nanoparticle-polymer-hybrid-based heterogeneous catalysts with high reactivity and good recyclability is highly desired for their applications in the chemical and pharmaceutical industries: Herein, we have developed a novel synthetic strategy by choosing a predesigned metal-anchored building block for in situ generation of metal (Pd) nanoparticles in the stable, porous, and crystalline covalent organic framework (COF), without using conventional reducing agents. In situ generation of Pd nanoparticles in the COF Skeleton is explicitly confirmed' from PXRD, XPS, TEM images, and N-15 NMR spectral analysis. This hybrid material is found to be an excellent reusable heterogeneous catalyst for the synthesis of biologically and pharmaceutically important 2-substituted benzofurans from 2-bromophencils and terminal alkynes via a tandem process with the turnover number up to 1101. The heterogeneity of the catalytic process is unambiguously verified by a mercury poisoning experiment and leaching test. This hybrid material shows superior catalytic performance compared to commercially available homogeneous as well as heterogeneous Pd catalysts.1 aBhadra, Mohitosh1 aSasmal, Himadri, Sekhar1 aBasu, Arghya1 aMidya, Siba, P.1 aKandambeth, Sharath1 aPachfule, Pradip1 aBalaraman, Ekambaram1 aBanerjee, Rahul uhttp://library.ncl.res.in/content/predesigned-metal-anchored-building-block-situ-generation-pd-nanoparticles-porous-covalent01242nas a2200181 4500008004100000022001400041245012700055210006900182260000800251300001400259490000700273520055300280100002200833700002000855700003000875700002500905856013000930 2018 eng d a1359-734500aPd(II)-Catalyzed gamma-C(sp(3))-H alkynylation of amides: selective functionalization of R chains of amides (RC)-C-1(O)NHR0 aPdIICatalyzed gammaCsp3H alkynylation of amides selective functi cJUL a7483-74860 v543 a

The gamma C(sp(3))-H bond alkynylation of R chains of amides (RC)-C-1(O)NHR, a fundamental class of synthetic substrates, has not been accomplished to date. Here, the first example of palladium(ii)-catalyzed alkynylation of an unactivated gamma C(sp(3))-H bond of alkyl amides (cyclic, linear, and amino acids) is reported. The kinetic experiment shows that the rate of the reaction depends on the coupling partners and the amides. Late-stage diversification of alkynylated amides was developed by utilizing amine and alkyne functionalities.

1 aLandge, Vinod, G.1 aParveen, Ayisha1 aNandakumar, Avanashiappan1 aBalaraman, Ekambaram uhttp://library.ncl.res.in/content/pdii-catalyzed-gamma-csp3-h-alkynylation-amides-selective-functionalization-r-chains-amides01173nas a2200205 4500008004100000022001400041245010200055210006900157260000800226300001200234490000600246520045100252100002200703700002700725700002000752700002600772700001900798700002500817856012500842 2018 eng d a2044-475300aPhosphine-free cobalt pincer complex catalyzed Z-selective semi-hydrogenation of unbiased alkynes0 aPhosphinefree cobalt pincer complex catalyzed Zselective semihyd cJAN a428-4330 v83 a

Herein, we report a novel, molecularly defined NNN-type cobalt pincer complex catalyzed transfer semi-hydrogenation of unbiased alkynes to Z-selective alkenes. This unified process is highly stereo-and chemo-selective and exhibits a broad scope as well as wide functional group tolerance. Ammonia-borane (AB), a bench-stable substrate with high gravimetric hydrogen capacity, was used as a safe and practical transfer hydrogenating source.

1 aLandge, Vinod, G.1 aPitchaimani, Jayaraman1 aMidya, Siba, P.1 aSubaramanian, Murugan1 aMadhu, Vedichi1 aBalaraman, Ekambaram uhttp://library.ncl.res.in/content/phosphine-free-cobalt-pincer-complex-catalyzed-z-selective-semi-hydrogenation-unbiased01927nas a2200241 4500008004100000022001400041245009800055210006900153260000800222300001400230490000600244520110600250653003301356653001601389653001901405653001301424653002501437100002101462700003101483700002001514700002501534856012601559 2018 eng d a2155-543500aPhotocatalysis enabling acceptorless dehydrogenation of diaryl hydrazines at room temperature0 aPhotocatalysis enabling acceptorless dehydrogenation of diaryl h cAUG a7727-77330 v83 a

Aromatic azo compounds are privileged structural motifs, and they exhibit a myriad of pharmaceutical as well as industrial applications. Here, we report a catalytic acceptorless dehydrogenation of diarylhydrazine derivatives to access a wide variety of aryl-azo compounds with the removal of molecular hydrogen as the sole byproduct. This distinctive reactivity has been achieved under dual catalytic conditions by merging the visible-light active [Ru(bpy)(3)](2+) as the photoredox catalyst and Co(dmgH)(2)(py)Cl as the proton-reduction catalyst. The reaction proceeds smoothly under very mild and benign conditions and operates at ambient temperature. This dual catalytic approach is highly compatible with many different functional groups and has a broad substrate scope. We have also demonstrated the reversible hydrogen storage and release phenomenon on hydrazobenzene/azobenzene couple to show the utility of these compounds as hydrogen storage materials. Further diversification of azobenzene was shown by a transition metal-catalyzed azo-group-directed ortho-C-H bond functionalization.

10aacceptorless dehydrogenation10aAzo benzene10adual catalysis10aHydrogen10aphotoredox catalysis1 aSahoo, Manoj, K.1 aSaravanakumar, Krishnasamy1 aJaiswal, Garima1 aBalaraman, Ekambaram uhttp://library.ncl.res.in/content/photocatalysis-enabling-acceptorless-dehydrogenation-diaryl-hydrazines-room-temperature01314nas a2200229 4500008004100000022001400041245011300055210006900168260000900237300001400246490000800260520053100268653003300799653001200832653001100844653001400855653001900869100001800888700002500906700002400931856012900955 2021 eng d a1615-415000aPhosphine-free manganese(II)-catalyst enables acceptorless dehydrogenative coupling of alcohols with indoles0 aPhosphinefree manganeseIIcatalyst enables acceptorless dehydroge cSEP  a4430-44390 v3633 aHerein, an air-stable, molecularly defined NNN-Mn(II) pincer complex catalyzed acceptorless dehydrogenative coupling of alcohols with indoles is reported. A wide variety of symmetrical and unsymmetrical bis(indolyl)methane derivatives as well as some structurally important products such as Vibrindole A, Turbomycin B alkaloid, Antileukemic, and Anticancer agents were synthesized. Mechanistic studies illustrate the importance of the NH moiety in the complex and the crucial role of metal-ligand cooperation during catalysis.10aacceptorless dehydrogenation10aAlcohol10aIndole10amanganese10aphosphine-free1 aYadav, Vinita1 aBalaraman, Ekambaram1 aMhaske, Santosh, B. uhttp://library.ncl.res.in/content/phosphine-free-manganeseii-catalyst-enables-acceptorless-dehydrogenative-coupling-alcohols