Coordinative Interactions between Porphyrins and C60, La@C82, and La2@C80

Authors

  • Dr. Takahiro Tsuchiya,

    1. Life Science Center of Tsukuba Advanced Research, Alliance, University of Tsukuba, Tsukuba 305-8577 (Japan)
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  • M. Sc. Marc Rudolf,

    1. Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität, Erlangen-Nürnberg (Germany)
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  • Dr. Silke Wolfrum,

    1. Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität, Erlangen-Nürnberg (Germany)
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  • Dr. Shankara Gayathri Radhakrishnan,

    1. Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität, Erlangen-Nürnberg (Germany)
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  • Ryo Aoyama,

    1. Life Science Center of Tsukuba Advanced Research, Alliance, University of Tsukuba, Tsukuba 305-8577 (Japan)
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  • Yuya Yokosawa,

    1. Life Science Center of Tsukuba Advanced Research, Alliance, University of Tsukuba, Tsukuba 305-8577 (Japan)
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  • Azusa Oshima,

    1. Life Science Center of Tsukuba Advanced Research, Alliance, University of Tsukuba, Tsukuba 305-8577 (Japan)
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  • Prof. Dr. Takeshi Akasaka,

    Corresponding author
    1. Life Science Center of Tsukuba Advanced Research, Alliance, University of Tsukuba, Tsukuba 305-8577 (Japan)
    • Life Science Center of Tsukuba Advanced Research, Alliance, University of Tsukuba, Tsukuba 305-8577 (Japan)
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  • Prof. Dr. Shigeru Nagase,

    1. Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103 (Japan)
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  • Prof. Dr. Dirk M. Guldi

    Corresponding author
    1. Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität, Erlangen-Nürnberg (Germany)
    • Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität, Erlangen-Nürnberg (Germany)
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Abstract

For the first time, a C60 derivative (1) and two different lanthanum metallofullerene derivatives, La@C82Py (2) and La2@C80Py (3), that feature a pyridyl group as a coordination site for transition-metal ions have been synthesized and integrated as electron acceptors into coordinative electron-donor/electron-acceptor hybrids. Zinc tetraphenylporphyrin (ZnP) served as an excited-state electron donor in this respect. Our investigations, by means of steady-state and time-resolved photophysical techniques found that electron transfer governs the excited-state deactivation in all of these systems, namely 1/ZnP, 2/ZnP, and 3/ZnP, whereas, in the ground state, notable electronic interactions are lacking. Variation of the electron-accepting fullerene or metallofullerene moieties provides the incentive for fine-tuning the binding constants, the charge-separation kinetics, and the charge-recombination kinetics. To this end, the binding constants, which ranged from log Kassoc=3.94–4.38, are dominated by axial coordination, with minor contributions from the orbital overlap of the curved and planar π systems. The charge-separation and charge-recombination kinetics, which are in the order of 1010 and 108 s−1, relate to the reduction potential of the fullerene and metallofullerenes, respectively.

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