Tuning of photochemical and photophysical properties of [RuII(2,2'-bipyridine)2Lx] complexes using nonchromophoric ligand variations

MO calculations were carried out on a cis-[Ru(bpy)2Lx](PF6) 2 complex, where bpy is 2,2'-bipyridine and L is 3-aminopyridine (complex 1 with x = 2), with the Gaussian 03 package using the DFT method. The electronic structure and molecular properties of 1 were characterized in vacuum and in acetonitrile solution, and the results were compared to those obtained from the complex with L = 5,6-bis(3-amidopyridine)-7-oxanorbornene (complex 2 with x = 1). The electronic spectra of 1 and 2 were investigated by TD-DFT. Experimental data from cyclic voltammetry, UV-visible spectroscopy, photochemical and photophysical experiments were compared to the theoretical data to discover the influence of L on the electronic transitions and to interpret the differences between the photochemical behaviors of these complexes.