title: Photoinduced δ electron transfer in phenylene bridged Mo2dimers.
abstract: Photoinduced electron transfer (ET) in Mo2dimers, [Mo2(DAniF)3]2(μ-E2C(ph)CE2) (DAniF = N,N'-di(p-anisyl)formamidinate, E = O or S), has been studied by femtosecond transient spectral techniques. Using a 355 nm laser pulse, the δ electrons on the Mo-Mo quadruple bonds are selectively excited and subsequent charge separation yields diradicals [Mo2]˙--ph-[Mo2]˙+and [Mo2]-ph˙--[Mo2]˙+. The charge separation (CS) and recombination (CR) rates are derived by fitting the decay kinetic data of the excited states. Surprisingly, it is found that the CR rate constants (kCR-1, ∼1012s-1) for [Mo2]˙--ph-[Mo2]˙+are larger than the data (kCR-2) for [Mo2]-ph˙--[Mo2]˙+by about one order of magnitude, although in the first case, the ET distance is doubled and the electronic coupling between the donor and acceptor is weaker. Optical analyses reveal that the free energy changes (ΔG°) for the two CR processes correspond to the δ → δ* and the metal (δ) to bridging ligand (π*) transition energies, respectively, and thus, the ET kinetics is dominated likely by the driving force (-ΔG°).
authors.affiliation: Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou 510632, China. tcyliu@jnu.edu.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Cheng
authors.affiliation: Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai 200092, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Optoelectronics Material and Technologies, Sun Yet-Sen University, Xingang West, Guangzhou 510275, China. stswh@mail.sysu.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou 510632, China. tcyliu@jnu.edu.cn and Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai 200092, China and State Key Laboratory of Optoelectronics Material and Technologies, Sun Yet-Sen University, Xingang West, Guangzhou 510275, China. stswh@mail.sysu.edu.cn.
authors.forename: Chun Y
authors.initials: CY
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Optoelectronics Material and Technologies, Sun Yet-Sen University, Xingang West, Guangzhou 510275, China. stswh@mail.sysu.edu.cn.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou 510632, China. tcyliu@jnu.edu.cn.
authors.forename: Miao
authors.initials: M
authors.lastname: Meng
authors.affiliation: State Key Laboratory of Optoelectronics Material and Technologies, Sun Yet-Sen University, Xingang West, Guangzhou 510275, China. stswh@mail.sysu.edu.cn.
authors.forename: Fang
authors.initials: F
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Optoelectronics Material and Technologies, Sun Yet-Sen University, Xingang West, Guangzhou 510275, China. stswh@mail.sysu.edu.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Optoelectronics Material and Technologies, Sun Yet-Sen University, Xingang West, Guangzhou 510275, China. stswh@mail.sysu.edu.cn.
authors.forename: Liang-Nian
authors.initials: LN
authors.lastname: Ji