MCM-41-supported ruthenium carbonyl cluster-derived catalysts for asymmetric hydrogenation reactions
DSpace at IIT Bombay
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Title |
MCM-41-supported ruthenium carbonyl cluster-derived catalysts for asymmetric hydrogenation reactions
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Creator |
INDRA, ARINDAM
BASU, SUSMIT KULKARNI, DHANASHREE G GOPINATH, CHINNAKONDA S BHADURI, SUMIT LAHIRI, GOUTAM KUMAR |
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Subject |
reaction kinetics
catalysts hydrogenation transmission electron microscopy x-ray photoelectron spectroscopy |
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Description |
The anionic ruthenium carbonyl cluster [Ru4(μ-H)3(CO)12]− has been ion-paired with (3-chloropropyl)trimethoxysilyl-cinchonidium or sparteinium groups chemically bound to the surfaces of MCM-41 [(MCM-41-)(-O)3SiCH2CH2CH2NR3+Cl−, NR3 = cinchonidine or sparteine]. The resultant materials have been characterized before and after use as hydrogenation catalysts by IR, XPS, and TEM. The molecular identity of the cluster is retained in the fresh catalysts, but under hydrogen pressure (≥30 bar) the carbonyl groups are lost. Ruthenium (0) and a small amount of Ru2+ can be observed on the fresh catalyst by XPS, while the used catalyst shows only Ru(0). TEM micrographs show retention of the MCM structure and no observable aggregation of metal. Under optimal conditions, good (≤75%) and observable (≤30%) enantioselectivities are obtained for the hydrogenations of methyl pyruvate and acetophenone, respectively. The enantioselectivity of the catalyst towards methylpyruvate hydrogenation is retained even with relatively high turnovers. This behavior is in sharp contrast to that of the Chini cluster [Pt12(CO)24]2−, derived analogous catalyst reported earlier by us.
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Publisher |
Elsevier
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Date |
2009-03-23T05:14:03Z
2011-11-25T20:13:27Z 2011-12-26T13:08:18Z 2011-12-27T05:56:18Z 2009-03-23T05:14:03Z 2011-11-25T20:13:27Z 2011-12-26T13:08:18Z 2011-12-27T05:56:18Z 2008 |
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Type |
Article
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Identifier |
Applied Catalysis A: General 344(1-2), 124-130
0926-860X http://dx.doi.org/10.1016/j.apcata.2008.04.009 http://hdl.handle.net/10054/1074 http://dspace.library.iitb.ac.in/xmlui/handle/10054/1074 |
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Language |
en
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