SYNTHESIS AND STRUCTURES OF THE DOUBLY BRIDGED DINUCLEAR COBALT(III) PEROXO COMPLEXES REN)CO(MU-O-2)(MU-SR)CO(TREN)](N-AMINOETHYL)AMINE, SR=THIOSULFATE(2-) AND BENZENETHIOLATE(1-)]() [TREN=TRIS(2)

Many dinuclear dioxygen-bridged cobalt(III) complexes have been report ed.(1) These compounds have been increasing in interest from the point of view of oxygen activation and selective or specific oxidation reac tions for organic molecules.(2) Recently, we communicated the novel sy nthesis of the (mu-peroxo)(mu-thiosulfato)cobalt(III) complex [(tren)C o(mu-O-2)(mu-S2O3)Co-(tren)](2+) [tren = tris(2-aminoethyl)amine] from [CoCl2(tren)]Cl and NH2(CH2)(n)NH2.H2Sx in the presence of activated charcoal.(3) The X-ray crystal structure reveals that the complex has an unprecedentedly large Co-O-O-Co torsion angle of 75.5(2)degrees as compared with those of the known doubly bridged peroxo complexes [N4Co (mu-O-2)(mu-X)CoN4](n+) (X = OH- and NH2-).(1) It would be interesting to discover whether such a large torsion angle is essential for other mu-peroxo, mu-sulfur doubly bridged complexes. Here we report the imp roved synthesis of [(tren)Co(mu-O-2)-(mu-S2O3)Co(tren)](2+) and the re lated four peroxo complexes [(tren)Co(mu-O-2)(mu-SR)Co(tren)](n+) [SR = SCH2CH2SO32-,SCH2CH2OH-, SC6H5-, and SCH2CH2N(CH2CH3)(2)(-)]. These complexes were obtained in relatively good yields and showed character istic UV/vis absorption spectra. X-ray crystal structures were determi ned for the two complexes with mu-S2O32- and mu-SC6-H-5(-).