title: Aggregate of alkoxy-bridged Re(I)-rectangles as a probe for photoluminescence quenching.
abstract: Alkoxy-bridged rhenium(I) rectangles [{(CO)(3)Re(mu-OR)(2)Re(CO)(3)}(2)(mu-bpy)(2)] (1, R = C(4)H(9); 2, R = C(8)H(17); 3, R = C(12)H(25); bpy = 4,4'-bipyridine) comprising long alkyl chains form optically transparent aggregates and exhibit luminescence enhancement in the presence of water. The aggregation of Re(I)-rectangle was followed using a light-scattering technique. Presumably, the enhanced luminescence efficiency resulted from restriction of torsional molecular motion in the aggregates. In addition, the rate of bimolecular quenching of Re(I)-aggregates in the triplet excited state by various electron donors (amines) and acceptors (quinones) was efficient. These results indicate that the excited state of aggregated Re(I) surfactants with an electron acceptor and donor facilitate the electron-transfer quenching process after they became preassociated inside the Re(I)-aggregated species. These synthesized compounds may be useful fluorescent materials in optoelectronic applications.
authors.affiliation: Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan.
authors.forename: P
authors.initials: P
authors.lastname: Thanasekaran
authors.forename: Jing-Yun
authors.initials: JY
authors.lastname: Wu
authors.forename: Bala
authors.initials: B
authors.lastname: Manimaran
authors.forename: T
authors.initials: T
authors.lastname: Rajendran
authors.forename: I-Jy
authors.initials: IJ
authors.lastname: Chang
authors.forename: S
authors.initials: S
authors.lastname: Rajagopal
authors.forename: Gene-Hsiang
authors.initials: GH
authors.lastname: Lee
authors.forename: Shie-Ming
authors.initials: SM
authors.lastname: Peng
authors.forename: Kuang-Lieh
authors.initials: KL
authors.lastname: Lu