title: Azobenzene-based ruthenium(ii) catalysts for light-controlled hydrogen generation.
abstract: Eight new ruthenium(ii) half-sandwich complexes containing azobenzene-appended pyridine (1), bipyridine (2-5) and phosphine (6 and 7) ligands have been synthesized and fully characterized. UV-vis spectroscopic studies showed that the trans-to-cis photoisomerization was strongly inhibited upon coordination to the metal centre in azopyridine-derived ligands 1 and 2, but it remained efficient in azobenzene-appended bipyridine (3-5) and phosphine (6 and 7) ligands. The complexes were tested as precatalysts for photo-controlled hydrogen generation by hydrolytic decomposition of ammonia-borane (AB). In situ irradiation of the reaction mixtures of compounds [Ru(p-Cym)(6)Cl]Cl and [Ru(p-Cym)(7)Cl]Cl induced a clear change in the catalytic reaction rate, serving as a proof of concept for light-controlled hydrogen generation.
authors.affiliation: Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country (UPV-EHU), 20080 San Sebastián, Spain. Zoraida_freixa@ehu.eus.
authors.forename: A
authors.initials: A
authors.lastname: Telleria
authors.affiliation: Laboratoire de Physique et Chimie de Nano-Objets, INSA-Toulouse, 135 Avenue de Rangueil, F-31077 Toulouse, France.
authors.forename: P W N M
authors.identifier: http://orcid.org/0000-0002-2165-7090
authors.initials: PW
authors.lastname: van Leeuwen
authors.affiliation: Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country (UPV-EHU), 20080 San Sebastián, Spain. Zoraida_freixa@ehu.eus and IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
authors.forename: Z
authors.identifier: http://orcid.org/0000-0002-2044-2725
authors.initials: Z
authors.lastname: Freixa