Oxidative functionalisation of alkanes: synthesis, molecular structure and catalytic implications of anionic vanadium(V) oxo and peroxo complexes containing bidentate <i>N,O</i> ligands
Shulpin, Georgiy B.
Nizova, Galina V.
Date de parution
Journal of the Chemical Society, Dalton Transactions, 1999//3169-3175
A mixture of [NBu<sub>4</sub>][VO<sub>3</sub>] and pyrazine-2-carboxylic acid (Hpca) in acetonitrile catalysed smoothly the reaction of alkanes RH (R = CH<sub>3</sub> or C<sub>6</sub>H<sub>11</sub>) with molecular oxygen (from air) and hydrogen peroxide to give the corresponding alkyl hydroperoxide ROOH as the primary product. The oxo and peroxo anions [VO<sub>2</sub>(pca)<sub>2</sub>]<sup>–</sup> and [VO(O<sub>2</sub>)(pca)<sub>2</sub>]<sup>–</sup>, isolated as the tetrabutylammonium or ammonium salts from acetonitrile solution and fully characterised by single crystal structure analyses, are assumed to be involved in the catalytic process. A screening of different <i>N,O</i> ligands showed Hpca to be the best co-catalyst, while anthranilic acid (Hana) proved to be almost inactive. The isolation and crystal structure analysis of the analogous oxo compound [NBu<sub>4</sub>][VO<sub>2</sub>(ana)<sub>2</sub>] showed a fundamental difference in the co-ordination of the bidentate <i>N,O</i> ligands which might explain the different catalytic activities: while in [VO<sub>2</sub>(pca)<sub>2</sub>]<sup>–</sup> the two pca ligands are bonded through a nitrogen and an oxygen atom (<i>N,O</i> co-ordination), in [VO<sub>2</sub>(ana)<sub>2</sub>]<sup>–</sup> the two ana ligands are co-ordinated <i>via</i> two oxygen atoms of the carboxylato group (<i>O,O</i> co-ordination).
Type de publication
Resource Types::text::journal::journal article
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