Spectroscopic and Electrochemical Properties of Electronically Modified Cycloplatinated Formazanate Complexes.

Formazanates are a class of monoanionic, chromophoric, redox-active chelating ligands, and until recently, the coordination chemistry of formazanates with third-row transition metals was unexplored. Described here is a series of heteroleptic cyclometalated platinum formazanate complexes of the type Pt(C^N)(Fz), where “C^N” is the cyclometalating ligand and “Fz” is the formazanate. This work includes a set of 14 complexes derived from four different cyclometalating ligands and five different formazans, greatly expanding the structural and electronic diversity of this class of complexes. The formazans fall into two major categories: triarylformazans with either electron-donating (Me, OMe) or electron-withdrawing (CN) para substituents, and even more electron-deficient diarylformazans where the center position of the backbone is a cyano group. Seven of the new compounds are characterized by single-crystal X-ray diffraction, and all are characterized by cyclic voltammetry and UV–vis absorption spectroscopy to...