title: Enhanced photocatalysis of rhenium(I) complex by light-harvesting periodic mesoporous organosilica.
abstract: This paper describes a new conceptual design for enhancement of photocatalytic CO(2) reduction of a rhenium(I) complex by light harvesting of periodic mesoporous organosilica (PMO). Mesoporous biphenyl-silica (Bp-PMO) anchoring fac-[Re(I)(bpy)(CO)(3)(PPh(3))](+)(OTf)(-) (bpy =2,2'-bipyridine; OTf = CF(3)SO(3)) in the mesochannels was synthesized by co-condensation of two organosilane precursors, 4,4'-bis(triethoxysilyl)biphenyl and 4-[4-{3-(trimethoxysilyl)propylsulfanyl}butyl]-4'-methyl-2,2'-bipyridine in the presence of a template surfactant, followed by coordination of a rhenium precursor, [Re(I)(CO)(5)(PPh(3))](+)(OTf)(-) to the bipyridine ligand in the mesochannels. The 280 nm light was effectively absorbed by the biphenyl groups in Bp-PMO, and the excited energy was funneled into the Re complex by resonance energy transfer, which enhanced photocatalytic CO evolution from CO(2) by a factor of 4.4 compared with direct excitation of the Re complex. Bp-PMO had an additional merit to protect the Re complex against a decomposition by UV irradiation. These results demonstrate the potential of PMOs as a light-harvesting antenna for designing various photoreaction systems, mimicking the natural photosynthesis.
authors.affiliation: Toyota Central R&D Laboratories, Inc., Nagakute, Aichi 480-1192, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takeda
authors.forename: Masataka
authors.initials: M
authors.lastname: Ohashi
authors.forename: Takao
authors.initials: T
authors.lastname: Tani
authors.forename: Osamu
authors.initials: O
authors.lastname: Ishitani
authors.forename: Shinji
authors.initials: S
authors.lastname: Inagaki