Mass Spectrometric and Vibrational Characterization of Reaction Intermediates in [Ru(bpy)(tpy)(H2O)]2+ Catalyzed Water Oxidation

• Published in: ChemPlusChem (Weinheim, Germany) Vol. 82; no. 5; pp. 691 - 694
• Main Authors: Voss, Jonathan M., Duffy, Erin M., Marsh, Brett M., Garand, Etienne
• Format: Journal Article
• Language: English
• Published: Germany 01.05.2017
• Subjects: catalysis; infrared spectroscopy; mass spectrometry; reaction intermediates; water oxidation; catalysis; mass spectrometry; reaction intermediates; water oxidation; infrared spectroscopy
• ISSN: 2192-6506; 2192-6506
• DOI: 10.1002/cplu.201700085

Mass spectrometry coupled with an in‐line electrochemical electrospray ionization source is used to capture some of the reaction intermediates formed in the [Ru(bpy)(tpy)(H2O)]2+ (bpy=2,2′‐bipyridine, tpy=2,2′:6′,2“‐terpyridine) catalyzed water oxidation reaction. By controlling the applied electrochemical potential, we identified the parent complex, as well as the first two oxidation complexes, identified as [Ru(bpy)(tpy)(OH)]2+ and [Ru(bpy)(tpy)(O)]2+. The structures of the parent and first oxidation complexes are probed directly in the mass spectrometer by using infrared predissociation spectroscopy of D2‐tagged ions. Comparisons between experimental vibrational spectra and density functional theory calculations confirmed the identity and structure of these two complexes. Moreover, the frequency of the O−H stretching mode in [Ru(bpy)(tpy)(OH)]2+ shows that this complex features a Ru–OH interaction that is more covalent than ionic. Capturing intermediates: Mass spectrometry coupled with an in‐line electrochemical electrospray ionization source was used to capture some of the reaction intermediates formed in the water oxidation reaction catalyzed by [Ru(bpy)(tpy)(H2O)]2+ (bpy=2,2′‐bipyridine, tpy=2,2′:6′,2“‐terpyridine). The [Ru(bpy)(tpy)(OH)]2+ structure was probed directly in the mass spectrometer by using infrared predissociation spectroscopy.