REACTION OF 3,5-DI-TERT-BUTYL-ORTHO-BENZOQUINONE ON CO(II)M(III) (M = Y, LA) HETERODINUCLEAR CENTERS - THE FORMATION AND ESR-SPECTRA OF CO(III)M(III) SEMIQUINONE ADDUCTS

The reactions of 3,5-di-t-butyl-o-benzoquinone (DBQ) with the Co(II)M(III) (M-Y, La) complexes of N,N'-bis(3-carboxysalicylidone)ethylenediamine have been studied in dmf solutions by means of ESR spectroscopy. The ESR spectral study has shown that DBQ oxidizes the Co(II) ion of the Co(II)M(III) complexes to afford a Co(III)M(III)-DBSQ species (DBSQ = semiquinone form of DBQ) but the DBSQ is bound to the M(III) ion but not to the Co(III). The reaction of the mononuclear cobalt(II) complex [Co(H2L)] with DBQ afforded [Co(II)2I.)(DBSQ)] where DBSQ coordinates to the cobalt(III) ion as a bidentate chelate.