Vibrational Characterization of a Ruthenium Water Oxidation Catalyst and Intermediates

This work focuses on a well-known molecular water oxidation catalyst, [Ru(tpy)(bpy)(OH₂)]²⁺, the simplest of a large family of ruthenium-based catalysts. Although there have been numerous chemical investigations of this catalyst and its many derivatives throughout the past decade, direct structural information and corresponding molecular level insight into its reactivity remained elusive. Presented here are infrared predissociation spectra of this catalyst and isolated intermediates of the proposed reaction pathway. With the aid of DFT calculations, previously proposed molecular structures are now strongly supported by spectroscopic evidence, and key intermolecular interactions that influence reactivity are probed.