FACILE ALDIMINE-]AMIDE OXIDATION IN A RHENIUM COMPLEX

The title reaction is illustrated by the quantitative chemical/electrochemical oxidation of LRe(III)Cl(3)(OPPh(3)) (1) (obtained from ReOCl3(PPh(3))(2) and L) to L'(ReCl3)-Cl-IV(OPPh(3)), (2) in aqueous acetonitrile media (L = N-p-tolylpyridine-2-aldimine; HL' = N-p-tolyl-2-picolinamide). Complexes 1 and 2 have been structurally characterized as their crystalline benzene solvates: 1.C6H6 and 2.1/2C(6)H(6). The oxidation of 1 to 2 probably proceeds via addition of a molecule water to the azomethine function of the intermediate LRe(IV)Cl(3)(OPPh(3))(+), 1(+) with subsequent rapid oxidation of the adduct. The moisture-sensitive complex 1(+) can be electrochemically generated in dry acetonitrile (E(1/2)(1(+)/1) = 0.30 V vs SCE).