Studies on the Control of Photoinduced Electron Transfer Reaction of Porphyrins by Amphiphilic Polyelectrolytes

环十二基(CD)是一种大体积、刚性的疏水基团，具有环状结构，共价连接在聚磺酸上，由于自组织，在水溶液中形成疏水团簇。因此，聚合物作为一个整体形成单分子胶束。与这种两亲性聚磺酸共价连接的锌(II)四苯基卟啉(ZnTPP)部分被发现紧密地分隔在Cd团簇中，导致非常不寻常的光物理和光化学性质。特别反常的是，在室温下，由于三重态激发态的热再布居而产生的磷光和E型延迟荧光是由水溶液中的分区化的ZnTPP部分发出的。这些不同寻常的观察主要是因为严格防止了三重态-三重态的湮灭，因为生色团在Cd团簇中彼此静态地隔离，并且还被保护而不受体水相的影响，因此在其寿命期间，ZnTPP三重态几乎没有机会相遇，也不受体相中的杂质的影响。这导致了即使在室温下的流体水溶液中也有非常长的三重态寿命。激光光解研究表明，在从长寿命三重态到自毁电子受体--硫酸盐的光致电子转移过程中，发生了有效的电子转移，并产生了来自ZnTPP及其受体的自由基。这种分隔的体系的一个特征是，ZnTPP阳离子自由基能持续很长时间(ESR可识别该自由基数小时)。

Cyclododecyl (Cd) groups, bulky and rigid hydrophobic goups with a ring structure, covalently attached to a polysulfonic acid were found to form hydrophobic clusters in aqueous solution due to self-organization. Thus, the polymer, as a whole, forms unimolecular micelle. Zinc(II) tetraphenylporphyrin (ZnTPP) moieties covalently linked to such an amphiphilic polysulfonic acid were found to be tightly compartmentalized in the Cd clusters, leading to very unusual photophysical and photochemical properties. Particularly anomalous behavior was that phosphorescence and E-type delayd fluorescence due to thermal repopulation from the triplet-excited state were emitted by the compartmentalized ZnTPP moieties in aqueous solution at room temperature. These unusual observations are primarily due to the fact that triplet-triplet annihilation is rigorously prevented because the chromophores are statically isolated in the Cd cluster from each other and also protected from the bulk aqueous phase such that the ZnTPP triplets have virtually no chance to encounter each other and also protected from impurities in the bulk phase during their lifetimes. This leads to enormously long triplet lifetime even in fluid aqueous solution at room temperature. In the photoinduced electron transfer from the ZnTPP long-lived triplets to sulfonium salts, self-destructive electron acceptors, as studied by laser photolysis, efficient electron transfer was found to occur and generate radicals coming from the ZnTPP and the acceptors. A characteristic feature of this compartmentalized ZnTPP system was that the ZnTPP cation radical persisted for extremely long time (the radical was recognized for several hours by ESR).