Ground and Excited state electronic structure of an Emissive Pyrazine-bridged Ruthenium(II) dinuclear complex

The synthesis, characterization, and electrochemical, photophysical, and photochemical properties of the binuclear compounds [(Ru(H-8-bpy)(2))(2)((Metr)(2)Pz)](PF6)(2) (1) and [(Ru(D-8-bpy)(2))(2)((Metr)(2)Pz)](PF6)(2) (2), where bpy is 2,2'-bipyridine and H-2(Metr)(2)Pz is the planar ligand 2,5-bis(5'-methyl-4'H-[1,2,4]triaz-3'-yl)-pyrazine, are reported. Electrochemical and spectro-electrochemical investigations indicate that the ground-state interaction between each metal center is predominantly electrostatic and in the mixed-valence form only a low level of ground-state delocalization is present. Resonance Raman, transient, and time-resolved spectroscopies enable a detailed assignment to be made of the excited-state photophysical properties of the complexes. Deuteriation is employed to both facilitate spectroscopic characterization and investigate the nature of the lowest excited states.