Photoinduced Energy and Electron Transfer Processes in Hexapyropheophorbide ai- Fullerene [C60] Molecular Systems

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• 作者：Martin Regehly ; Eugeny A. Ermilov ; Matthias Helmreich ; Andreas Hirsch ; Norbert Jux ; Beate R&ouml ; der
• 刊名：Journal of Physical Chemistry B
• 出版年：2007
• 出版时间：February 8, 2007
• 年：2007
• 卷：111
• 期：5
• 页码：998 - 1006
• 全文大小：300K
• 年卷期：v.111,no.5(February 8, 2007)
• ISSN：1520-5207

文摘

The photophysical properties of the novel hexapyropheophorbide a (P6), and hexakis (pyropheophorbidea)-C₆₀ (FP6) were studied and compared with those of hexakis (pyropheophorbide a)-fullerene [5:1] hexaadduct(FHP6). It was found that after light absorption the pyropheophorbide a molecules in all three compoundsundergo very efficient energy transfer as well as partly excitonic interactions. The last process results in theformation of energy traps, which could be resolved experimentally. For P6, due to shorter distances betweenneighboring dye molecules, stronger interactions between pyropheophorbide a units than for FHP6 wereobserved. As a consequence, the excitation energy is delivered rapidly to traps formed by stackedpyropheophorbide a molecules resulting in the reduction of fluorescence, intersystem crossing, and singletoxygen quantum yields compared to the values of FHP6. For FP6 the reduction of these values is muchstronger due to an additional fast and efficient deactivation process, namely photoinduced electron transferfrom pyropheophorbide a to the fullerene moiety. Consequently, FP6 can be considered as a combination ofa light-harvesting system consisting of several separate pyropheophorbide a molecules and a charge-separatingcenter.