A Charge-Stabilizing, Multimodular, Ferrocene–Bis(triphenylamine)–Zinc-porphyrin–Fullerene Polyad

Authors

  • Dr. Channa A. Wijesinghe,

    1. Department of Chemistry, Wichita State University, Wichita, KS 67260-0051 (USA)
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  • Dr. Mohamed E. El-Khouly,

    1. Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan), Fax: (+81) 6-6879-7370
    2. Current address: Department of Chemistry, Faculty of Science, Kafr ElSheikh University (Egypt)
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  • Prof. Melvin E. Zandler,

    1. Department of Chemistry, Wichita State University, Wichita, KS 67260-0051 (USA)
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  • Prof. Shunichi Fukuzumi,

    Corresponding author
    1. Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan), Fax: (+81) 6-6879-7370
    2. Department of Bioinspired Science Ewha Womans University, Seoul 120-750 (Korea)
    • Shunichi Fukuzumi, Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan), Fax: (+81) 6-6879-7370

      Francis D'Souza, Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX 76203-5017 (USA), Fax: (+1) 940-565-4318

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  • Prof. Francis D'Souza

    Corresponding author
    1. Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX 76203-5017 (USA), Fax: (+1) 940-565-4318
    • Shunichi Fukuzumi, Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan), Fax: (+81) 6-6879-7370

      Francis D'Souza, Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX 76203-5017 (USA), Fax: (+1) 940-565-4318

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Abstract

A novel multimodular donor–acceptor polyad featuring zinc porphyrin, fullerene, ferrocene, and triphenylamine entities was designed, synthesized, and studied as a charge-stabilizing, photosynthetic-antenna/reaction-center mimic. The ferrocene and fullerene entities, covalently linked to the porphyrin ring, were distantly separated to accomplish the charge-separation/hole-migration events leading to the creation of a long-lived charge-separated state. The geometry and electronic structures of the newly synthesized compound was deduced by B3LYP/3-21G(*) optimization, while the energy levels for different photochemical events was established using data from the optical absorption and emission, and electrochemical studies. Excitation of the triphenylamine entities revealed singlet-singlet energy transfer to the appended zinc porphyrin. As predicted from the energy levels, photoinduced electron transfer from both the singlet and triplet excited states of the zinc porphyrin to fullerene followed by subsequent hole migration involving ferrocene was witnessed from the transient absorption studies. The charge-separated state persisted for about 8.5 μs and was governed by the distance between the final charge-transfer product, that is, a species involving a ferrocenium cation and a fullerene radical anion, with additional influence from the charge-stabilizing triphenylamine entities located on the zinc-porphyrin macrocycle.

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