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

• Published in: Inorganica Chimica Acta 2011-08, Vol.374 (1), p.435-441
• Main Authors: Murphy, Damien M., McNamara, Kenneth, Richardson, Patricia, Sanchez-Romaguera, Veronica, Winpenny, Richard E.P., Yellowlees, Lesley J.
• Format: Article
• Language: English
• Subjects: 1,10-Phenanthroline; DFT calculations; Electrochemistry; EPR spectroelectrochemistry
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2011.02.050

The redox chemistry of 1,10-phenanthroline-5,6-dione and N,N′- and O,O′-bound complexes of Pt, Pd and Ru is presented. Stable redox states are characterised by UV–Vis, EPR and IR spectroscopies. [Display omitted] ► Redox studies of 1,10-phenanthroline-5,6-dione and its Pt, Pd and Ru complexes. ► N,N′-bound complexes undergo facile reversible one-electron reduction. ► O,O′-bound complex has reversible one-electron oxidation at low temperature. ► EPR, UV–Vis and DFT results indicate CO groups electronically important. Electrochemical and spectroelectrochemical (UV–Vis, IR, EPR) of pd (pd=1,10-phenanthroline-5,6-dione), Pt(N,N′-pd)Cl2, Pd(N,N′-pd)Cl2, [Ru(bpy)2(N,N′-pd)]Cl2 (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 −1.25V 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 pd1−. The mode of coordination of pd has a greater influence on its redox chemistry than the metal centre or the ancillary ligands.