Photodehydrogenation of alcohols catalysed by a single ruthenium N-Heterocyclic carbene complex

• Published in: Journal of catalysis Vol. 448; p. 116134
• Main Authors: Ibáñez-Ibáñez, Laura, Guisado-Barrios, Gregorio, Mata, José A.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.08.2025
• Subjects: Benzylic alcohols; carbenes; Dehydrogenation; heterocyclic nitrogen compounds; hydrogen; hydrogen production; Hydrogen storage; light; liquids; LOHCs; Photocatalysis; Ruthenium; Single catalyst; Single catalyst; Hydrogen storage; Ruthenium; Dehydrogenation; Photocatalysis; LOHCs; Benzylic alcohols
• ISSN: 0021-9517
• DOI: 10.1016/j.jcat.2025.116134

[Display omitted] •A ruthenium complex catalyses the photodehydrogenation of benzylic alcohols in water to render the carboxylate salts and two molecules of H2.•A standalone ruthenium complex plays a dual task harvesting visible light and being responsible for the bond breaking/forming event.•Blue visible light enhances the hydricity of the Ru-H bond facilitating the generation and release of H2 under mild conditions.•The presence of an NHC ligand bearing methyl and pyrenylmethylene substituents at the azole ring are key for the observed catalytic performance.•This molecular complex is postulated as a competent contender for future hydrogen storage technologies. The transition metal catalyzed dehydrogenation of alcohols to carboxylate salts and H2 is an attractive tool due to their potential use as LOHCs (Liquid Organic Hydrogen Carriers). Still, most current methods encompass harsh conditions and two steps synthesis. Herein, we describe an efficient ruthenium(II) catalyzed hydrogen production from benzylic alcohols to the corresponding carboxylate derivatives assisted by visible light. Our photocatalytic system comprises a standalone N-heterocyclic carbene based piano stool ruthenium complex playing a dual role, harvesting visible-light and enabling H2 generation under mild conditions in aqueous media.