@article { ISI:000240781100009,
	title = {Effect of spacer groups on the performance of MCM-41-supported platinum cluster-derived hydrogenation catalysts},
	journal = {Journal of Catalysis},
	volume = {242},
	number = {2},
	year = {2006},
	month = {SEP},
	pages = {332-339},
	publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE},
	type = {Article},
	address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA},
	abstract = {<p>MCM-41 was functionalized with (EtO)(3)SiCH2Cl, (MeO)(3)SiCH2CH2CH2Cl, and (CH3)Cl2SiCH2Cl. The functionalized materials were characterized by solid-state NMR (CPMAS, Si-29 and C-13) and XPS. The NMR data indicate that three new silicon environments were created by(EtO)(3)SiCH2Cl and (MeO)(3)SiCH2CH2CH2Cl, whereas with (CH3)Cl2SiCH2Cl, two new silicon environments were obtained. XPS results from Si 2p core level and the valence band from the material functionalized by (MeO)(3)Si(CH2)(3)Cl was found to be the same as that of the corresponding fresh catalyst (1a), in contrast to that of the materials functionalized by the other two silane reagents. After further functionalization with triethylamine, these materials were used as inorganic anion exchangers to support the cluster anion [Pt-12(CO)(24)](2-). Solid-state NMR (29Si, C-13, N-15) was used to establish the presence of the quaternary ammonium group in the cluster-supported species. Analogous materials were also created using fumed silica as the support, and all of the cluster-supported materials were tested as catalysts for the hydrogenation of methyl pyruvate, acetophenone, nitrobenzene, benzonitrile, ethylacetoacetate, 4-nitrotoluene, cyclohexanone, allyl alcohol, and styrene. The best activity was obtained for the catalyst that had MCM-41 as the support and chloropropyl as the spacer group. TEM showed that the supports and the spacer groups had observable effects on the platinum crystallite size of the catalysts. (c) 2006 Elsevier Inc. All rights reserved.</p>},
	keywords = {functionalized inorganic oxides, hydrogenation catalysts, MCM-41, platinum carbonyl cluster, Solid-state NMR, spacer groups, XPS},
	issn = {0021-9517},
	doi = {10.1016/j.jcat.2006.06.016},
	author = {Maity, Niladri and Basu, Susmit and Mapa, Maitri and Rajamohanan, Pattuparambil R. and Ganapathy, Subramanian and Gopinath, Chinnakonda S. and Bhaduri, Sumit and Lahiri, Goutam Kumar}
}
@article { ISI:000236419800016,
	title = {MCM-41-supported platinum carbonyl cluster-derived catalysts for asymmetric and nonasymmetric hydrogenation reactions},
	journal = {Journal of Catalysis},
	volume = {239},
	number = {1},
	year = {2006},
	month = {APR},
	pages = {154-161},
	publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE},
	type = {Article},
	address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA},
	abstract = {<p>Anionic platinum carbonyl Cluster ([Pt-12(CO)(24)](2-)) was ion-paired with the 3-chloropropyltrimethoxysilyl-ammonium group chemically bound to the surface of MCM-41. The materials undergo quick decarbonylation and have been characterized before decarbonylation by IR and UV-vis spectroscopy and after decarbonylation by XPS and TEM. They have been used as catalysts for the hydrogenations of methyl pyruvate, acetophenone, nitrobenzene, benzonitrile, and ethylacetoacetate. The support and the quaternary ammonium groups have significant effects on surface platinum concentration, crystallite size, and observed activity. In the hydrogenation of the prochiral substrates methyl pyruvate or acetophenone, the cinchonidine-based catalyst gives significant enantioselectivity under optimum conditions. A kinetic model that includes an enantioselective product-formation step and a hydrogen pressure-dependent step for the deactivation of the enantioselective sites gives reasonable agreement between predicted and observed enantioselectivity. The model is also in accordance with the XPS and TEM data. (c) 2006 Elsevier Inc. All rights reserved.</p>},
	keywords = {asymmetric/non-asymmetric catalysis, Enantioselectivity, functionalized MCM-41, hydrogenation catalysts, platinum carbonyl cluster},
	issn = {0021-9517},
	doi = {10.1016/j.jcat.2006.01.032},
	author = {Basu, Susmit and Mapa, Maitri and Gopinath, Chinnakonda S. and Doble, Mukesh and Bhaduri, Sumit and Lahiri, Goutam Kumar}
}
