Synthesis, spectroscopic, and electrochemical properties of bis(2,2′-bipyridyl)-ruthenium compounds of some pyridyl-1,2,4-triazoles

A series of bis(2,2′-bipyridyl)ruthenium compounds with pyridin-2-yl-1,2,4-triazoles has been prepared and characterised by their 1H and 13C n.m.r. spectra and their electronic and electrochemical properties. The 1H n.m.r. spectra have been used to ascertain the co-ordination mode of the ligands. The ligands bind in a bidentate fashion and they have π-acceptor properties that are weaker than 2,2′-bipyridyl (bipy). The excited-state properties of the complexes are similar to those of [Ru(bipy)3]2+ but important variations in the energies of the absorption and the emission maxima are observed.