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Osmium(0) nanoclusters stabilized by zeolite framework; highly active catalyst in the aerobic oxidation of alcohols under mild conditions.
MedLine Citation:
PMID:  20614055     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Abstract/OtherAbstract:
Osmium(0) nanoclusters stabilized by zeolite-Y framework were reproducibly prepared by a simple two step procedure involving the incorporation of osmium(III) cations into the zeolite matrix by ion-exchange, followed by their reduction within the cavities of zeolite with sodium borohydride in aqueous solution all at room temperature. The composition and morphology of osmium(0) nanoclusters stabilized by zeolite framework, as well as the integrity and crystallinity of the host material were investigated by using ICP-OES, XRD, XPS, SEM, TEM, HRTEM, TEM/EDX, mid-IR, far-IR spectroscopies, and N(2)-adsorption/desorption technique. The results of the multiprong analysis reveal the formation of osmium(0) nanoclusters within the cavities of zeolite-Y without causing alteration in the framework lattice, formation of mesopores, or loss in the crystallinity of the host material. More importantly, far-IR studies showed that after the reduction of Os(3+) cations by sodium borohydride the Na(+) cations reoccupy their authentic cation sites restoring the integrity of zeolite-Y. The catalytic activity of osmium(0) nanoclusters stabilized by zeolite framework was tested in the aerobic oxidation of activated, unactivated and heteroatom containing alcohols to carbonyl compounds and was found to provide high activity and selectivity even under mild conditions (80 degrees C and 1 atm O(2) or air). Moreover, they were found to be stable enough to be isolated and bottled as solid material, which can be reused as active catalyst under the identical conditions of the first run.
Authors:
Mehmet Zahmakiran; Serdar Akbayrak; Tetsuya Kodaira; Saim Ozkar
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Publication Detail:
Type:  Journal Article     Date:  2010-07-07
Journal Detail:
Title:  Dalton transactions (Cambridge, England : 2003)     Volume:  39     ISSN:  1477-9234     ISO Abbreviation:  Dalton Trans     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-08-04     Completed Date:  2010-12-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101176026     Medline TA:  Dalton Trans     Country:  England    
Other Details:
Languages:  eng     Pagination:  7521-7     Citation Subset:  -    
Affiliation:
Department of Chemistry, Middle East Technical University, 06531, Ankara, Turkey.
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