Molecular Architecture and Environmental Effects in Intramolecular Electron Transfer. An Electron Paramagnetic Resonance Study
Molecular Architecture and Environmental Effects in Intramolecular Electron Transfer. An Electron Paramagnetic Resonance Study
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分子内电子转移的分子结构和环境影响。
DOI：
10.1021/j100019a037
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
K. Moebius
中科院分区：
文献类型：
--
作者：
K. Hasharoni;H. Levanon;Joerg Gaetschmann;H. Schubert;H. Kurreck;K. Moebius
利用连续波时间分辨电子顺磁共振（CW-TREPR）技术研究了三种光合作用模型体系中的分子内电子转移（ET）：（1）锌卟啉（ZnTPP）通过酰胺基与荧光黄素（PaF）连接;（2）ZnTPP通过苯基基与苯醌在帕拉（p-PpQ）连接;（3）在Meta位（m-PpQ）连接。各向异性液晶环境使得ET产物在宽的温度范围内可检测，即210< T< 330 K。在这样的实验条件下，ET速率相当显著地降低到溶剂控制的绝热区。谱线形状的差异反映了分子结构的影响，即供体-受体以及间隔基部分的相对取向。分子结构的这些差异通过自旋-自旋耦合（J）和偶极相互作用（D）的大小由TREPR谱表现出来，从而导致不同的电子自旋极化机制。
Intramolecular electron transfer (ET) in three photosynthetic model systems, orientedin liquid crystals (LCs), was monitored by continuous wave time-resolved electron paramagnetic resonance(CW-TREPR) spectros-copy:(1) zinc porphyrin (ZnTPP) linked via an amide spacer to a lumiflavin (PaF);(2) ZnTPP linked to a benzoquinone via a phenyl spacer in the para (p-PpQ); and (3) in the meta (m-PpQ) positions. The anisotropic liquid crystalline environment makes the ET products detectable over a wide range of temperatures, ie, 210< T< 330 K. Under such experimentalconditions the ET rates are reduced quite dramatically into the solvent controlled adiabatic regime. The spectral line shape differences reflect the effect of the molecular architecture, namely, the relative orientation of the donor—acceptor as well as the spacer moiety. These differences in molecular structures are manifested by the TREPR spectra through the magnitude of the spin-spin coupling (J) and the dipolar interaction (D), thus leading to different electron spin polarization mechanisms.