Formation, Spectral, Electrochemical, and Photochemical Behavior of Zinc N-Confused Porphyrin Coordinated to Imidazole Functionalized Fullerene Dyads

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• 作者：Francis D'Souza ; Phillip M. Smith ; Lisa Rogers ; Melvin E. Zandler ; D.-M. Shafiqul Islam ; Yasuyaki Araki ; and Osamu Ito
• 刊名：Inorganic Chemistry
• 出版年：2006
• 出版时间：June 26, 2006
• 年：2006
• 卷：45
• 期：13
• 页码：5057 - 5065
• 全文大小：393K
• 年卷期：v.45,no.13(June 26, 2006)
• ISSN：1520-510X

文摘

Donor-acceptor dyads were constructed using zinc N-confused porphyrin (ZnNCP), a structural isomer of zinctetraphenylporphyrin, as a donor, and fullerene as an electron acceptor. Two derivatives, pyridine-coordinated zincN-confused porphyrin (Py:ZnNCP) and the zinc N-confused porphyrin dimer (ZnNCP-dimer) were utilized to formthe dyads with an imidazole-appended fulleropyrrolidine (C₆₀Im). These porphyrin isomers formed well-defined 1:1supramolecular dyads (C₆₀Im:ZnNCP) via axial coordination. The dyads were characterized by optical absorptionand emission, ESI-mass, ¹H NMR, and electrochemical methods. The binding constant, K, was found to be 2.8 ×10⁴ M^-1 for C₆₀Im:ZnNCP. The geometric and electronic structure of C₆₀Im:ZnNCP were probed by using DFTB3LYP/3-21G(*) methods. The HOMO was found to be on the ZnNCP entity, while the LUMO was primarily on thefullerene entity. The electrochemical properties of C₆₀Im:ZnNCP was probed using cyclic voltammetry ino-dichlorobenzene, 0.1 n-Bu₄NClO₄. The Py:ZnNCP was found to be easier to oxidize by over 340 mV comparedto Py:ZnTPP. Upon dyad formation via axial coordination, the first oxidation revealed an anodic shift of nearly 90mV. Evidence of photoinduced charge separation from the singlet excited ZnNCP to the appended fullerene wasestablished from time-resolved emission and nanosecond transient absorption studies.