A series of asymmetrical bis-tridentate cyclometalated complexes including [Ru(Mebib)(Mebip)] +, [Ru(Mebip)(dpb)] +, [Ru(Mebip)(Medpb)] +, and [Ru(Mebib)(tpy)] + and two bis-tridentate noncyclometalated complexes [Ru(Mebip) 2] 2+ and [Ru(Mebip)(tpy)] 2+ were prepared and characterized, where Mebib is bis(N-methylbenzimidazolyl)benzene, Mebip is bis(N-methylbenzimidazolyl) pyridine, dpb is 1,3-di-2-pyridylbenzene, Medpb is 4,6-dimethyl-1,3-di-2- pyridylbenzene, and tpy is 2,2′:6′,2″-terpyridine. The solid-state structure of [Ru(Mebip)(Medpb)] + is studied by X-ray crystallographic analysis. The electrochemical and spectroscopic properties of these ruthenium complexes were studied and compared with those of known complexes [Ru(tpy)(dpb)] + and [Ru(tpy) 2] 2+. The change of the supporting ligands and coordination environment allows progressive modulation of the metal-associated redox potentials (Ru II/III) from +0.26 to +1.32 V vs Ag/AgCl. The introduction of a ruthenium cyclometalated bond in these complexes results in a significant negative potential shift. The Ru II/III potentials of these complexes were analyzed on the basis of Lever's electrochemical parameters (E L). Density functional theory (DFT) and time-dependent DFT calculations were carried out to elucidate the electronic structures and spectroscopic spectra of complexes with Mebib or Mebip ligands.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry