Electrochemical and spectroelectrochemical studies of complexes of 1,10-phenanthroline-5,6-dione

Electrochemical and spectroelectrochemical (UV-Vis, IR, EPR) of pd (pd = 1,10-phenanthroline-5, 6-dione), Pt(N,N'-pd)Cl-2, Pd(N,N'-pd)Cl-2, [Ru(bpy)(2)(N,N'-pd)]Cl-2 (bpy = 2,2'-bipyridine) and Pt(O,O'-pd)(PPh3)(2), where N,N' and O,O' refers to coordination of pd to the metal centre via N and O atoms, respectively, reveals that the electron transfer processes between +0.5 and -1.25 V all occur at the pd ligand in agreement with DFT calculations. The two CO groups carry a significant amount of the negative charge in mono-reduced pd(1). The mode of coordination of pd has a greater influence on its redox chemistry than the metal centre or the ancillary ligands. (C) 2011 Elsevier B. V. All rights reserved.