David W. Thompson, James F. Wishart, Bruce S. Brunschwig and Norman Sutin
J. Phys. Chem. A, 105, 8117-8122 (2001) [Find paper at ACS Publications]
Abstract:
The relaxation dynamics and product distribution resulting from the decay of high lying excited states generated via sequential two-photon capture by [Ru(bpy)3]2+ or electron capture by [Ru(bpy)3]3+ have been investigated by flash photolysis and pulse radiolysis techniques. In comparison to the decay dynamics for monophotonic excitation, dramatically different relaxation dynamics have been observed. High-power flash excitation yields both the lowest lying metal-to-ligand charge transfer (3MLCT) state and a new transient photoproduct associated with nonradiative decay through the photodissociative metal-centered (3dd) excited state/s. The photoproduct is postulated to be [RuII(bpy)2(eta1-bpy)]2+ where the pendant pyridine has rotated to yield a transient that is stabilized by a pi-bonded or a three-centered Ru-C-H agostic interaction.