Exploring the photo-stability of the {Ru(py)4}2+ fragment
Abstract Mononuclear Ru(II) tetrakis-pyridine species of general formula trans- [(Cl)Ru(py) 4 (X)] n + (X = Cl − , MeCN and CO) are thermally inert toward ligand exchange reactions at room temperature, but undergo substitution under photolysis conditions. The carbonyl derivative trans -[(Cl)Ru II (py) 4 (CO)] + was specifically synthesized for this report by the direct reaction between trans -[(Cl)Ru II (py) 4 (Solv)] + and CO in acetone and isolated as a PF 6 − salt. Stationary photolysis experiments in MeCN allowed recording changes in the absorption profiles along time providing quantitative values for the quantum yields of the different photo-processes, which involve the consecutive loss of CO, MeCN or pyridine ligands. There is no evidence of photo-release of a chloride anion in none of the molecules under study. For X = CO and MeCN the photo-release of X is favored over the substitution of a pyridine molecule.