Light Energy Collection in a Porphyrin–Imide–Corrole Ensemble

Authors

  • Adina I. Ciuciu,

    1. Istituto per la Sintesi Organica e la Fotoreattività (ISOF), CNR, Via P. Gobetti 101, 40129 Bologna (Italy)
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  • Dr. Lucia Flamigni,

    Corresponding author
    1. Istituto per la Sintesi Organica e la Fotoreattività (ISOF), CNR, Via P. Gobetti 101, 40129 Bologna (Italy)
    • Lucia Flamigni, Istituto per la Sintesi Organica e la Fotoreattività (ISOF), CNR, Via P. Gobetti 101, 40129 Bologna (Italy)

      Daniel T. Gryko, Institute of Organic Chemistry of the Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland)

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  • Dr. Roman Voloshchuk,

    1. Institute of Organic Chemistry of the Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland)
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  • Prof. Dr. Daniel T. Gryko

    Corresponding author
    1. Institute of Organic Chemistry of the Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland)
    2. Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)
    • Lucia Flamigni, Istituto per la Sintesi Organica e la Fotoreattività (ISOF), CNR, Via P. Gobetti 101, 40129 Bologna (Italy)

      Daniel T. Gryko, Institute of Organic Chemistry of the Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland)

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Abstract

An assembly consisting of three units, that is, a meso-substituted corrole (), 1,8 naphthaleneimide (), and a Zn porphyrin (), has been synthesized. NIE is connected to C3 through a 1,3-phenylene bridge and to the ZnP unit through a direct C[BOND]C bond. The convergent synthetic strategy includes the preparation of a trans-A2B-corrole possessing the imide unit, followed by Sonogashira coupling with a meso-substituted A3B-porphyrin. The photophysical processes in the resulting triad are examined and compared with those of the corresponding dyad and the constituent reference models , , and . Excitation of the NIE unit in leads to a fast energy transfer of 98 % efficiency to C3 with a rate ken=7.5×1010 s−1, whereas excitation of the corrole unit leads to a reactivity of the excited state identical to that of the model , with a deactivation rate to the ground state k=2.5×108 s−1. Energy transfer to C3 and to ZnP moieties follows excitation of NIE in the triad . The rates are ken=7.5×1010 s−1 and ken=2.5×1010 s−1 for the sensitization of the C3 and ZnP unit, respectively. The light energy transferred from NIE to Zn porphyrin unit is ultimately funneled to the corrole component, which is the final recipient of the excitation energy absorbed by the different components of the array. The latter process occurs with a rate ken=3.4×109 s−1 and 89 % efficiency. Energy transfer processes take place in all cases by a Förster (dipole–dipole) mechanism. The theory predicts quite satisfactorily the rate for the ZnP/C3 couple, where components are separated by about 23 Å, but results in calculated rates that are one to two orders of magnitude higher for the couples NIE/ZnP (D/A) and NIE/C3, which are separated by distances of about 14 and 10 Å, respectively.

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