SYNTHESIS, PROPERTIES AND CHARACTERIZATION OF THE TRINUCLEAR CLUSTERS[CO-3(MU-SR)(6)(PET(3))(3)]X (R=ME OR ET, X=BPH(4)(-) OR PF6-)

The reactions of methane- and ethane-thiol with cobalt(II) acetate in the presence of an excess of PEt(3) afforded the new clusters [Co-3(mu -SR)(6)(PEt(3))(3)]X (R = Me or Et, X = BPh(4)(-) or PF6-). A complete X-ray analysis of [Co-3(mu-SEt)(6)(PEt(3))(3)]BPh(4) revealed that in the cluster cation the three cobalt atoms are at the vertices of a re gular triangle, with six equivalent symmetrically bridging thiolate li gands. A multinuclear magnetic resonance study showed that the singly charged duster molecules in solution maintain essentially the same con formation as in the solid state, the thiolate groups being involved in a rapid dynamic process. Electrochemical measurements showed that the se cluster monocations undergo both a one-electron oxidation and a one -electron reduction. The latter is complicated by degradation of the c orresponding neutral congeners. The electrogenerated paramagnetic comp ounds were studied by EPR analysis and the resulting features correlat ed with the results of an extended-Huckel molecular orbital study.