title: Subtle Changes to Peripheral Ligands Enable High Turnover Numbers for Photocatalytic Hydrogen Generation with Supramolecular Photocatalysts.
abstract: The photocatalytic generation of hydrogen (H2) from protons by two cyclometalated ruthenium-platinum polypyridyl complexes, [Ru(bpy)2(2,5-bpp)PtIS](2+) (1) and [Ru(dceb)2(2,5-bpp)PtIS](2+) (2) [where bpy = 2,2'-bipyridine, 2,5-bpp = 2,2',5',2″-terpyridine, dceb = 4,4'-di(carboxyethyl)bipyridine, and S = solvent], is reported. Turnover numbers (TONs) for H2 generation were increased by nearly an order of magnitude by the introduction of carboxyethyl ester units, i.e., from 80 for 1P to 650 for 2P after 6 h of irradiation, with an early turnover frequency (TOF) increasing from 15 to 200 h(-1). The TON and TOF values for 2P are among the highest reported to date for supramolecular photocatalysts. The increase correlates with stabilization of the excited states localized on the peripheral ligands of the light-harvesting Ru(II) center.
authors.affiliation: Institut für Anorganische Chemie I, Universität Ulm , Albert-Einstein-Allee 11, 89081 Ulm, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Kowacs
authors.affiliation: SRC for Solar Energy Conversion, School of Chemical Sciences, Dublin City University , Dublin 9, Ireland.
authors.forename: Laura
authors.initials: L
authors.lastname: O'Reilly
authors.affiliation: Optical Sciences group, MESA + Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Qing
authors.initials: Q
authors.lastname: Pan
authors.affiliation: Optical Sciences group, MESA + Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Huijser
authors.affiliation: Institut für Anorganische Chemie I, Universität Ulm , Albert-Einstein-Allee 11, 89081 Ulm, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Lang
authors.affiliation: Institut für Anorganische Chemie I, Universität Ulm , Albert-Einstein-Allee 11, 89081 Ulm, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Rau
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Wesley R
authors.initials: WR
authors.lastname: Browne
authors.affiliation: SRC for Solar Energy Conversion, School of Chemical Sciences, Dublin City University , Dublin 9, Ireland.
authors.forename: Mary T
authors.initials: MT
authors.lastname: Pryce
authors.affiliation: SRC for Solar Energy Conversion, School of Chemical Sciences, Dublin City University , Dublin 9, Ireland.
authors.forename: Johannes G
authors.initials: JG
authors.lastname: Vos