Ligand field states dominate excited state decay in trans-[Ru(py)4Cl2] MLCT chromophores

Abstract In this contribution, the ultrafast excited state dynamics of a family of trans-[Ru(L)4Cl2] metal to ligand charge transfer chromophores, where L = pyridine, 4-tert-butylpyridine, 4-methoxypyridine and 4,4′-bipyridine, are studied using a combination of femtosecond transient absorption spectroscopy and (TD)DFT theoretical methods. Ligand field states were directly observed and found to dominate the excited state decay cascade, leading to ligand photosubstitution. The internal conversion process that feeds ligand field states, indirectly after light absorption, occurs prior to thermal relaxation in