Abstract
The excited-state version of the Creutz-Taube ion was prepared via visible light excitation of [(NH(3) )(5) Ru(II) (μ-pz)Ru(II) (NH(3) )(5) ](4+) . The resulting excited state is a mixed valence {Ru(III-δ) (μ-pz⋅(-) )Ru(II+δ) } transient species, which was characterized using femtosecond transient absorption spectroscopy with vis-NIR detection. Very intense photoinduced intervalence charge transfers were observed at 7500 cm(-1) , revealing an excited-state electronic coupling element H(DA) =3750 cm(-1) . DFT calculations confirm a strongly delocalized excited state. A notable consequence of strong electron delocalization is the nanosecond excited state lifetime, which was exploited in a proof-of-concept intermolecular electron transfer. The excited-state Creutz-Taube ion is established as a reference, and demonstrates that electron delocalization in the excited state can be leveraged for artificial photosynthesis or other photocatalytic schemes based on electron transfer chemistry.