Polyoxometalates alkanes

Oxygenation of alkanes with hydrogen peroxide in homogeneous reactions can be obtained also with Keggin-type iron-substituted polyoxometalates. Evidence against radical reactions has been offered. 

Very few methods have been reported for direct aerobic oxidation of alkanes using a perfluorinated ruthenium catalyst [Ru30(0C0CF2CF2CF3)6(Et20)3] [120c] and a ruthenium-substituted polyoxometalate [WZnRu2(0H)(H20)(ZnW9034)2] (Eqs. 3.102 and 3.103) [159, 160[. 

Organic substrates (alkanes alkenes, alcohols) are also photooxidized by trans-dioxo Ru and Os complexes [93]. The interest in these catalysts may lie in the transformation of cyclohexane to cyclohexanone and cyclohexanol in reasonable yields. The presence of alcohol, ester, and ketone functional groups is tolerated in the catalytic functionalization [94] with polyoxometallates and Pt as co-catalyst [95]. 

N. Mizumo, C. Nozaki, 1. Kiyoto, M. Misono, Highly efficient utilization of hydrogen peroxide for selective oxygenation of alkanes catalyzed by Diiron-substituted polyoxometalate precursor, J. Am. Chem. Soc. 120 (1998) 9267. 

N. Muradov, M. Rustamov, and Yu. Bazhutin, Photoactivation of methane and other alkanes using silica-supported polyoxometalates, Proc. Acad. Sciences USSR, 312 139 (1990)... 

Selective Oxygenation of Alkanes Catalyzed by Diiron-Substituted Polyoxometalate Precursor, J. 

VIII 3D. ALKANE FUNCTIONALIZATION UNDER THE ACTION OE POLYOXOMETALATES... 

Polyoxometalates (POMs) are widely used in various oxidations, particularly of saturated hydrocarbons [81]. In this section, we will discuss only POM-promoted transformations of alkanes which occur in the absence of oxygen... 

Renneke, R., Kadkhodayan, M., Pasquah, M., etal. (1991). Roles of Surface Protonation on the Photodynamic, Catalytic, and Other Properties of Polyoxometalates Probed by the Photochemical Functionalization of Alkanes. Implications for Irradiated Semiconductor Metal Oxides, J. Am. Chem. Soc., 113, pp. 8357-8367. 

Mizuno, N., Nozaki, C., Kiyoto, L, etal. (1998). Highly Efficient UtUization of Hydrogen Peroxide for Selective Oxygenation of Alkanes Catalyzed by Diiron-Snbstituted Polyoxometalate Precursor, J. Am. Chem. Soc., 120, pp. 9267-9272. 

Neumann, R. and Khenkin, A. (1995). Noble Metal (Ru, Pd, Pt ) Substituted Sandwich Type Polyoxometalates Preparation, Characterization, and Catalytic Activity in Oxidations of Alkanes and AUcenes by Peroxides, Inorg. Chem., 34, pp. 5753—5760. 

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