@article { ISI:000253646100010, title = {Enantioselective hydrogenation of olefins by chiral iridium phosphorothioite complex covalently anchored on mesoporous silica}, journal = {Journal of Catalysis}, volume = {254}, number = {1}, year = {2008}, month = {FEB}, pages = {91-100}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

Chiral monodentate phosphorous-based ligands have proven effective for the enantioselective hydrogenation of olefins. Binol-derived monodentate phosphorothioite (PS) ligand was synthesized from binol and thiopropyltriethoxysilane, and its iridium complex was covalently anchored to mesoporous silica supports like SBA-15, MCM-41, and MCM-48. These catalysts were characterized by different physicochemical techniques and assessed for their catalytic performances in the heterogeneous asymmetric hydrogenation of itaconic acid and its derivatives. It was found that the catalytic activities and enantioselectivities of the heterogenized iridium complex (IrPSSBA-15) in the hydrogenation reactions were comparable to its homogeneous analogue. Binol-derived monodentate phosphorothioite ligand in heterogeneously anchored form (iridium complex) is a more effective catalyst than the reported monodentate phosphorous ligand systems in the hydrogenation reactions, possibly due to the changes in electronic properties around the iridium metal center. The effects of substrate-to-catalyst molar ratio, solvents, and temperature on substrate conversions and enantioselectivities, of the products were investigated in hydrogenation reactions. (c) 2007 Elsevier Inc. All rights reserved.

}, keywords = {binol, Enantioselective hydrogenation, Immobilization, iridium complex, itaconic acid, Mesoporous silica SBA-15, monodentate ligand, phosphorothioite ligand}, issn = {0021-9517}, doi = {10.1016/j.jcat.2007.12.002}, author = {Sahoo, Suman and Kumar, Pradeep and Lefebvre, F. and Halligudi, Shivaraj B.} } @article { ISI:000265811500009, title = {Mesoporous silica immobilized cobalt complex: an efficient catalyst for epoxides ring opening by aromatic amines under ambient conditions}, journal = {Catalysis Communications}, volume = {10}, number = {10}, year = {2009}, month = {MAY}, pages = {1398-1403}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

{Cobalt complex, CobpbH(2)Cl(2)2H(2)O [where

}, keywords = {beta-Amino alcohols, CobpbH(2)Cl(2)2H(2)O complex, Epoxide ring opening, Immobilization, SBA-15}, issn = {1566-7367}, doi = {10.1016/j.catcom.2009.03.005}, author = {Bordoloi, Ankur and Hwang, Young Kyu and Hwang, Jin-Soo and Halligudi, Shivaraj B.} } @article { ISI:000293288500004, title = {Ordered mesoporous silica as supports in the heterogeneous asymmetric catalysis}, journal = {Catalysis Surveys from Asia}, volume = {15}, number = {3}, year = {2011}, month = {SEP}, pages = {200-214}, publisher = {SPRINGER/PLENUM PUBLISHERS}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Enantioselective synthesis of organic compounds has been studied by homogeneous catalysts for several years. However, these catalysts have yet to make a significant impact on industrial scales for fine chemical synthesis. A primary reason is the designing of a homogeneous asymmetric catalyst, which requires relatively bulky ligands and catalyst recovery and recycling often causes problems. One of the convincing ways to overcome this problem is to immobilise the asymmetric catalyst onto a solid support and the resulting heterogeneous asymmetric catalyst system can, in principle, be readily re-used. A large number of supports such as inorganic oxides including zeolites, alumina, zirconia, silica and organic polymers have been employed as supports in heterogeneous asymmetric catalysis. Therefore, in this review article we have summarized the work done by us in our laboratory on the immobilization of chiral transition metal complexes such as Ru, Ir, Mn and Ti onto ordered mesoporous silica and its asymmetric catalysis. All these immobilized catalysts were well characterized by different physicochemical techniques to confirm the structural retention of the support as well as the active metal complex after immobilization. This report includes our asymmetric catalytic investigations in enantioselective reactions such as hydrogenation of ketones, olefins, oxidation of sulfides and oxidative kinetic resolution of alcohols and sulfoxides through immobilized heterogeneous catalyst systems.

}, keywords = {Enantioselective hydrogenation, Enantioselective oxidation, Immobilization, Mesoporous silica, Oxidative kinetic resolution}, issn = {1571-1013}, doi = {10.1007/s10563-011-9122-z}, author = {Sahoo, Suman and Bordoloi, Ankur and Halligudi, Shivaraj B.} }