Control of Redox Potential by Deprotonation of Coordinated 1<i>H</i>‐Imidazole in Complexes of 2‐(1<i>H</i>‐Imidazol‐2‐yl)pyridine

Abstract

Abstract Complexes [ML 3 ] 2+ of the bidentate ligand 2‐(1 H ‐imidazol‐2‐yl)pyridine were prepared with iron(II), cobalt(II), and ruthenium(II). The electronic spectra suggest the ligand to be a weaker σ ‐donor and π ‐acceptor than the closely related 2,2′‐bipyridine. The complexes are readily deprotonated by addition of base, and the effect of the deprotonation is to lower the M III /M II redox potential by roughly 900 mV. This is roughly 75% of the drop observed for related complexes of 2,6‐di‐1 H ‐imidazol‐2‐ylpyridine, and suggests the effect to be largely coulombic in origin.