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.