Abstract: An extended series of ligands and their copper (11) complexes have been prepared as spectroscopic models for determining the geometries and ligand coordinations of copper proteins. The electronic properties of thioether, imidazole, amide anion, amine, phenolate anion, and thiolate anion coordination to copper (I1) have been determined. In addition, the electronic spectra of some of these ligands in square-planar, square- ...