Formation of Electronically Excited Products in Electron-Transfer Reactions: Reaction of Polypyridine Complexes of Cobalt(I) and Ruthenium(III) in Acetonitrile

Article abstract of DOI:10.1021/ja00268a006

The yields of the metal-to-ligand charge-transfer excited state of poly(pyridine)ruthenium(II) complexes (*RuL₃(2+)) produced in the reaction of RuL3(3+) with poly(pyridine)cobalt(I) complexes in acetonitrile have been measured by use of a combination of continuous flow methods and chemical actinometry.The *RuL₃(2+) yields are high, ranging from 0.31 +/- 0.04 for the most exergonic system (Ru(bpy)3(3+) and Co(4,4'-(CH3)2bpy)3(3+)) to 0.07 +/- 0.02 for the least exergonic system studied (Ru(4,7-(CH3)2phen)3(3+) and Co(bpy)3(1+)).The results are interpreted in terms of competing electron-transfers channel yielding primarily *RuL₃(2+) + CoL₃(2+) and RuL₃(2+) + *CoL₃(2+) (²T), with the formation of entirely ground-state products being negligible.A new actinometer consisting of Os(terpy)2(2+) and Co(NH3)5Cl(2+), for use at wavelengths up to ca. 720 nm, is described.