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- Title
High Catalytic Activity of Heterometallic (Fe<sub>6</sub>Na<sub>7</sub> and Fe<sub>6</sub>Na<sub>6</sub>) Cage Silsesquioxanes in Oxidations with Peroxides.
- Authors
Yalymov, Alexey I.; Bilyachenko, Alexey N.; Levitsky, Mikhail M.; Korlyukov, Alexander A.; Khrustalev, Victor N.; Shul'pina, Lidia S.; Dorovatovskii, Pavel V.; Es'kova, Marina A.; Lamaty, Frédéric; Bantreil, Xavier; Villemejeanne, Benoît; Martinez, Jean; Shubina, Elena S.; Kozlov, Yuriy N.; Shul'pin, Georgiy B.
- Abstract
Two types of heterometallic (Fe(III),Na) silsesquioxanes--[Ph5Si5O10]2[Ph10Si10O21]Fe6(O2-)2Na7 (H3O+)(MeOH)2(MeCN)4.5.1.25(MeCN), I, and [Ph5Si5O10]2[Ph4Si4O8]2Fe6Na6(O2-)3(MeCN)8.5(H2O)8.44, II--were obtained and characterized. X-ray studies established distinctive structures of both products, with pair of Fe(III)-O-based triangles surrounded by siloxanolate ligands, giving fascinating cage architectures. Complex II proved to be catalytically active in the formation of amides from alcohols and amines, and thus becoming a rare example of metallasilsesquioxanes performing homogeneous catalysis. Benzene, cyclohexane, and other alkanes, as well as alcohols, can be oxidized in acetonitrile solution to phenol--the corresponding alkyl hydroperoxides and ketones, respectively--by hydrogen peroxide in air in the presence of catalytic amounts of complex II and trifluoroacetic acid. Thus, the cyclohexane oxidation at 20 °C gave oxygenates in very high yield of alkanes (48% based on alkane). The kinetic behaviour of the system indicates that the mechanism includes the formation of hydroxyl radicals generated from hydrogen peroxide in its interaction with di-iron species. The latter are formed via monomerization of starting hexairon complex with further dimerization of the monomers.
- Subjects
CATALYSIS; PEROXIDES; SILICONES
- Publication
Catalysts (2073-4344), 2017, Vol 7, Issue 4, p101
- ISSN
2073-4344
- Publication type
Article
- DOI
10.3390/catal7040101