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 [LCo^IIICu^IIICo^IIIL](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 (Cu^II, 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.