Photoinduced Electron Transfer and Excitation Energy Transfer in Directly Linked Zinc Porphyrin/Zinc Phthalocyanine Composite
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- 作者：Fuyuki Ito ; Yukihide Ishibashi ; Sazzadur Rahman Khan ; Hiroshi Miyasaka ; Kazuya Kameyama ; Mitsuhiko Morisue ; Akiharu Satake ; Kazuya Ogawa ; Yoshiaki Kobuke
- 刊名：Journal of Physical Chemistry A
- 出版年：2006
- 出版时间：November 30, 2006
- 年：2006
- 卷：110
- 期：47
- 页码：12734 - 12742
- 全文大小：214K
- 年卷期：v.110,no.47(November 30, 2006)
- ISSN：1520-5215
文摘
Photoinduced electron transfer (ET) and excitation energy transfer (ENT) reactions in monomer and slipped-cofacial dimer systems of a directly linked Zn porphyrin (Por)-Zn phthalocyanine (Pc) heterodyad, ZnPc-ZnPor, were investigated by means of the picosecond and femtosecond transient absorption spectroscopies.In the dimer dyad system of two heterodyads connected through the coordination bond between two imidazolyl-substituted ZnPor bearing ZnPc, ZnPc-ZnPor(D), the rapid ENT from the ZnPor to ZnPc in the subpicosecondtime region was followed by photoinduced charge separation (CS) and charge recombination (CR) with timeconstants of 47 and 510 ps, respectively. On the other hand in the monomer dyad system, no clear charge-separated state was observed although the CS with a time constant of 200 ps and CR with 
70 ps wereestimated. These results indicated that the dimer slipped-cofacial arrangement of pair porphyrins is advantageousfor the effective production of the CS state. This advantage was discussed from the viewpoint of a decreasein the reorganization energy of the dimer relative to that of the monomer system. In addition, the electrochemicalmeasurements indicated that the strong interaction between ZnPc and ZnPor moieties also contributed to thefast CS process despite the marginal driving force for the CS process. The dimer dyad of ZnPc-ZnPor providesfull advantages in efficiencies of the light harvesting and the CS state production.
70 ps wereestimated. These results indicated that the dimer slipped-cofacial arrangement of pair porphyrins is advantageousfor the effective production of the CS state. This advantage was discussed from the viewpoint of a decreasein the reorganization energy of the dimer relative to that of the monomer system. In addition, the electrochemicalmeasurements indicated that the strong interaction between ZnPc and ZnPor moieties also contributed to thefast CS process despite the marginal driving force for the CS process. The dimer dyad of ZnPc-ZnPor providesfull advantages in efficiencies of the light harvesting and the CS state production.