title: Syntheses, characterization, and photo-hydrogen-evolving properties of tris(2,2'-bipyridine)ruthenium(II) derivatives tethered to an H2-evolving (2-phenylpyridinato)platinum(II) unit.
abstract: With the aim of developing new molecular devices having higher photo-hydrogen-evolving activity, Pt(ppy)ClX units (ppy = 2-phenylpyridinate, X = Cl(-) or DMSO; DMSO = dimethylsulfoxide) have been employed as an H(2)-evolving site, as the catalytic activity of [Pt(ppy)Cl(2)](-) was confirmed to be higher than those of other mononuclear platinum(II) complexes. In the present study, two new heterodinuclear Ru(II)Pt(II) complexes, produced by condensation of [Ru(bpy)(2)(5-amino-phen)](2+) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) with [Pt(cppy)Cl(2)](-) and Pt(cppy)(DMSO)Cl (cppy = 9-carboxy-phenylpyridinate), respectively, have been prepared and their photo-hydrogen-evolving activities have been evaluated in detail. The ineffectiveness of these systems as photo-hydrogen-evolving molecular devices are interpreted in terms of their negative driving forces for the photoinduced electron transfer from the triplet MLCT excited state of the Ru chromophore to the pi*(ppy) orbital of the catalyst moiety.
authors.affiliation: Department of Chemistry, Faculty of Science, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Masaoka
authors.forename: Ken
authors.initials: K
authors.lastname: Sakai
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry; D004583:Electrons; D006859:Hydrogen / Q000737:chemistry*; D008024:Ligands; D055668:Photochemical Processes; D010984:Platinum / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D008024:Ligands; D010984:Platinum; D015082:2,2'-Dipyridyl; D012428:Ruthenium; D006859:Hydrogen