Vanadium‐Catalysed Aerobic Cleavage of C−C Bonds in Substituted Cyclohexanones To Afford Carboxylic Acids: Two Model Complexes with Tetrahedral Geometry around Vanadium(V)

Autor: Maxence Vennat, Jean-Marie Brégeault, Patrick Herson, Georgiy B. Shul'pin
Rok vydání: 2003
Předmět:
Zdroj: European Journal of Inorganic Chemistry. 2003:908-917
ISSN: 1099-0682
1434-1948
DOI: 10.1002/ejic.200390120
Popis: Two monosilanol/disilanol derivatives were synthesised by treatment of Ph3SiOH or Ph2Si(OH)2 with [nBu4N]VO3 (3) in ethanol solution. The mononuclear anionic dioxo vanadium(V) species [{Ph3SiO}2VO2]− (4) and the dinuclear complex anion [{Ph2SiO2VO2}2]2− (5) thus obtained are unusual and novel model compounds with ≡Si−O−V(O)2O linkages characterised by single-crystal X-ray diffraction. The catalytic activities of these tert-butylammonium complexes, together with those of the simple vanadium derivatives 3 and 5, of the vanadyl precursors VOSO4·5H2O (1) and [VO(acac)2] (2), and also of “H6[PMo9V3O40]·aq”, were tested for aerobic C−C bond cleavage in 2-hydroxycyclohexanone and 2-methylcyclohexanone. Monomeric vanadium species show the same chemistry as the polyoxometalate but with lower yields of acids or keto acids, and so the redox and acid properties of HPA-n (n = 3, 4) are better tuned. Mechanisms for these oxidation reaction, including electron transfer from a substrate coordinated to vanadium, are proposed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Databáze: OpenAIRE
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