Toward synthetic analogues of linked redox and catalytic multimetal sites in proteins: A model of the histidine-cysteine bridged dicopper array

Contiguous HisCys residues link a type 1 Cu electron-transfer site to a catalytic Cu-containing site in nitrite reductase and the multicopper oxidases. In efforts to understand the role of the linker in these multimetallic arrays and to design new catalysts, a mixed-valent dicopper complex comprising a bridging thiolate/N-donor ligand that models the CuHisCysCu motif was prepared and characterized by X-ray crystallography. Comparison of spectroscopic and cyclic voltammetry data to those of the mononuclear analogues of each portion of the complex, LCuSCPh₃ and LCu-(py) (L = β-diketiminate, py = pyridyl), confirmed retention of the dicopper structure in solution.