title: Homogeneous photocatalytic hydrogen production using π-conjugated platinum(II) arylacetylide sensitizers.
abstract: Three platinum(II) terpyridylacetylide charge-transfer complexes possessing a lone ancillary ligand systematically varied in phenylacetylide π-conjugation length, [Pt((t)Bu(3)tpy)([C≡CC(6)H(4)](n)H)]ClO(4) (n = 1-3), are evaluated as photosensitizers (PSs) for visible-light-driven (λ > 420 nm) hydrogen production in the presence of a cobaloxime catalyst and the sacrificial electron donor triethanolamine (TEOA). Excited-state reductive quenching of the PS by TEOA produces PS(-) (k(q) scales with the driving force as 1 > 2 > 3), enabling thermal electron transfer to the cobalt catalyst. The initial H(2) evolution is directly proportional to the incident photon flux and visible-light harvesting capacity of the sensitizer, 3 > 2 > 1. The combined data suggest that PSs exhibiting attenuated bimolecular reductive quenching constants with respect to the diffusion limit can overcome this deficiency through improved light absorption in homogeneous H(2)-evolving compositions.
authors.affiliation: Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, USA.
authors.forename: Xianghuai
authors.initials: X
authors.lastname: Wang
authors.forename: Sébastien
authors.initials: S
authors.lastname: Goeb
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Ji
authors.forename: Nadezhda A
authors.initials: NA
authors.lastname: Pogulaichenko
authors.forename: Felix N
authors.initials: FN
authors.lastname: Castellano