- 作者: 林瑞僩,何東英,楊吉水
- 作者服務機構: The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
- 中文摘要:
Emission from charge recombination between radical cations and anions of 9-cyano-10-(p-substituted phenyl)anthracenes (RA, where R is 10-p-substituted phenyl: R = Phenyl (PA), anisyl (OA), p-N,N-dimethylaminophenyl (NA), N,N-di-p-anisylaminophenyl (DA)), as donor-acceptor type molecules, generated during the pulse radiolysis in benzene was measured together with the transient absorption of RA radical cations (RA·+) and anions (RA·-). Based on the transient absorption and density functional theory (DFT-B3LYP/6-31G*) calculation, a twisted geometry is assumed for all RA in the ground state, RA·+, and RA·-. It is suggested that the positive charge of PA·+, OA·+, and NA·+ is delocalized on two moieties, and that of DA·+ is localized on the donor N,N-di-p-anisylaminophenyl moiety, while the negative charge of all RA·- is mainly on the acceptor 9-(10-cyano)anthracenyl moiety. When both RA·+ and RA·- are generated with sufficiently high concentrations during the pulse radiolysis in benzene, the charge recombination between RA·+ and RA·- occurred to give RA in the singlet excited state (1RA*) as the emissive species, but not the excimers because of the twisted geometries of RA·+ and RA·- with the large torsional angles between the 9-(10-cyano)anthracenyl and p-substituted phenyl moieties. Not only the fluorescence quantum yield of 1RA* but also the energy differences between the annihilation enthalpy change and the excitation energy of 1RA* are important factors for the radiolysis induced emission intensity of RA in benzene.
Emission from charge recombination between radical cations and anions of 9-cyano-10-(p-substituted phenyl)anthracenes (RA, where R is 10-p-substituted phenyl: R = Phenyl (PA), anisyl (OA), p-N,N-dimethylaminophenyl (NA), N,N-di-p-anisylaminophenyl (DA)), as donor-acceptor type molecules, generated during the pulse radiolysis in benzene was measured together with the transient absorption of RA radical cations (RA·+) and anions (RA·-). Based on the transient absorption and density functional theory (DFT-B3LYP/6-31G*) calculation, a twisted geometry is assumed for all RA in the ground state, RA·+, and RA·-. It is suggested that the positive charge of PA·+, OA·+, and NA·+ is delocalized on two moieties, and that of DA·+ is localized on the donor N,N-di-p-anisylaminophenyl moiety, while the negative charge of all RA·- is mainly on the acceptor 9-(10-cyano)anthracenyl moiety. When both RA·+ and RA·- are generated with sufficiently high concentrations during the pulse radiolysis in benzene, the charge recombination between RA·+ and RA·- occurred to give RA in the singlet excited state (1RA*) as the emissive species, but not the excimers because of the twisted geometries of RA·+ and RA·- with the large torsional angles between the 9-(10-cyano)anthracenyl and p-substituted phenyl moieties. Not only the fluorescence quantum yield of 1RA* but also the energy differences between the annihilation enthalpy change and the excitation energy of 1RA* are important factors for the radiolysis induced emission intensity of RA in benzene. - 英文摘要: --
- 中文關鍵字: Radical cation; Radical anion; Charge recombination; Pulse radiolysis; DFT calculation.
- 英文關鍵字: --