Reduction of nitrosoarene ligands in binuclear palladium(ii) complexes

Abstract

Reduction of the binuclear PdII complexes Pd2(OCOR)2(o-CH2C6H4—NO)2 (1) and Pd2(OCOR)2(o-PhN—C6H4—NO)2 (2) (where R = Me, CF3, But, or Ph) by sodium borohydride, an ethanolic solution of KOH, or molecular hydrogen was examined. The first stage of reduction was demonstrated to afford metallic palladium and aromatic amines, viz., o-toluidine o-Me—C6H4—NH2 from complex 1 and aniline Ph—NH2 from complex 2. The reactions with molecular hydrogen involve deeper stages to yield cyclic ketones (o-methylcyclohexanone and cyclohexanone) and then cycloalkanes (methylcyclohexane and cyclohexane, respectively). The latter reactions are accompanied by elimination of N2. The mechanism of reduction of complexes 1 and 2 with molecular hydrogen was proposed.