A Paramagnetic Copper(III) Complex Containing an Octahedral CuIIIS6 Coordination Polyhedron

Only the second octahedral, paramagnetic copper(III) complex (S=1) has now been synthesized and characterized. Six thiolato bridging ligands in the heterotrinuclear species [LCoIIICuIIICoIIIL](ClO4)3⋅2 Me2CO (L=1,4,7-tris(4-tert-butyl-2-sulfidobenzyl)-1,4,7-triazacyclononane) stabilize this rare electron configuration. A section of the structure of the reduced form (CuII, S=½) is shown. XAS, EXAFS, and EPR spectroscopy prove unambiguously that the one-electron oxidation to the copper(III) is metal- rather than ligand-centered.