Sequential Energy and Electron Transfer in an Artificial Reaction Center: Formation of a Long-Lived Charge-Separated State
Sequential Energy and Electron Transfer in an Artificial Reaction Center: Formation of a Long-Lived Charge-Separated State
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DOI：
10.1021/ja993959z
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发表时间：
2000-06
影响因子：
15
通讯作者：
C. Luo;D. Guldi;H. Imahori;and Koichi Tamaki;Y. Sakata
中科院分区：
文献类型：
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作者：
C. Luo;D. Guldi;H. Imahori;and Koichi Tamaki;Y. Sakata
通过将富勒烯部分连接到两个卟啉的阵列（即，锌四苯基卟啉（ZnP）和游离碱四苯基卟啉（H2 P））。在这个ZnP-H2 P-C60三元组中，ZnP作为天线分子，将其单重激发态能量转移到能量较低的H2 P。在苯甲腈中，这种能量转移（k = 1.5 × 1010 s-1）之后是一个连续的电子转移中继，从生成的H2 P单重激发态演化为ZnP− H2 P·+−C60·-，随后是ZnP·+− H2 P −C60·-，速率常数分别为7.0 × 109 s-1和2.2 × 109 s-1。最后的电荷分离态以高产率（0.4）形成，在脱氧苄腈中产生了21 μs的寿命，并直接衰变到单重基态。相反，在非极性甲苯溶液中，卟啉发色团（ZnP和H2 P）的失活通过单线态-单线态能量转移发生。
A novel molecular triad, representing an artificial reaction center, was synthesized via linking a fullerene moiety to an array of two porphyrins (i.e., a zinc tetraphenyl porphyrin (ZnP) and a free base tetraphenyl porphyrin (H2P)). In this ZnP−H2P−C60 triad, the ZnP performs as an antenna molecule, transferring its singlet excited state energy to the energetically lower lying H2P. In benzonitrile, this energy transfer (k = 1.5 × 1010 s-1) is followed by a sequential electron-transfer relay evolving from the generated singlet excited state of H2P to yield ZnP−H2P•+−C60•- and subsequently ZnP•+−H2P−C60•- with rate constants of 7.0 × 109 s-1 and 2.2 × 109 s-1, respectively. The final charge-separated state, formed in high yield (0.4), gives rise to a remarkable lifetime of 21 μs in deoxygenated benzonitrile and decays directly to the singlet ground state. In contrast, in nonpolar toluene solutions the deactivation of the porphyrin chromophores (ZnP and H2P) takes place via singlet−singlet energy transfer l...