Magnetophotoselection in the Spin-Polarized Triplet State Radical-Ion Pair Formed in the Photo-Induced Solvent-Mediated Electron Transfer Reaction from N,N-Diethylaniline to Xanthone in Viscous
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- 作者：Asako Ishigaki ; Yasuhiro Kobori ; Hisao Murai
- 刊名：Journal of Physical Chemistry A
- 出版年：2009
- 出版时间：January 29, 2009
- 年：2009
- 卷：113
- 期：4
- 页码：633-638
- 全文大小：183K
- 年卷期：v.113,no.4(January 29, 2009)
- ISSN：1520-5215
文摘
The triplet state radical-ion pair (RIP) formed in the photolysis of xanthone (Xn) and N,N-diethylaniline (DEA) in a highly viscous mixtures of 2-propanol and cyclohexanol was studied by time-resolved ESR. As the viscosity of the mixed solution increases, the spectrum reveals a magnetic dipole−dipole interaction in the triplet state of the RIP. Immediately after laser photolysis, the spin-polarized RIP spectrum exhibits magnetophotoselection (MPS). This suggests that the electron transfer (ET) reaction is faster than the longitudinal relaxation of the excited triplet state of Xn (3Xn*) or much faster than the tumbling motion of 3Xn*. The former mechanism is likely under the conditions employed. Indeed, a huge RIP-cored aggregation is quickly formed with solvent molecules which obstruct the free revolution of the RIP. The MPS spectra also indicate that only the molecules closely located react by the solvent-mediated ET.