Time-resolved X-Ray Absorption Spectroscopy of Solvated [Ru(m-bpy)3]2+ Complex: Electronic Structures of 3dd State

Abstract

Ru L-3-edge time-resolved X-ray absorption spectroscopy (TR-XAS) was applied to unravel photo-induced excited state dynamics of solvated [Ru(m-bpy)(3)](2+) (m-bpy = 6-methyl-2,2 '-bipyridine) complex. The Ru L-3-edge probes 2p core-level transitions, enabling to monitor the electronic structure of excited (3)dd state. TR-XAS and time-dependent density functional theory were utilized to directly visualize the charge density of (3)dd state around the Ru atom during the relaxation cascade of [Ru(m-bpy)(3)](2+) complex. The formation of (3)dd state is attributed to the reduced effective ligand field strength, which was derived from the TR-XAS of (3)dd state at 100 ps. These results highlight the role of ligand-field (3)dd state in the photo-induced relaxation dynamics of [Ru(m-bpy)(3)](2+) complex.