Probing inter-ligand excited state interaction in homo and heteroleptic ruthenium(II) polypyridyl complexes using selective deuteriation

The effect of deuteriation on the photophysical properties of two series of regioselectively deuteriated Ru(II) complexes ([Ru(bipy)x(ph2phen)3−x]2+, where x = 0–3 and ph2phen is 4,7-diphenyl-1,10-phenanthroline and [Ru(bipy)2(dcbipy2−)], where H2dcbipy is 4,4′-dicarboxy-2,2′-bipyridyl) is reported. Although overall, deuteriation results in an increase in emission lifetime for all complexes, the effect of substitution of hydrogen for deuterium shows strong regioselectivity both in terms of the ligand and the position on individual ligands that are exchanged.