title: Engaging Copper(III) Corrole as an Electron Acceptor: Photoinduced Charge Separation in Zinc Porphyrin-Copper Corrole Donor-Acceptor Conjugates.
abstract: An electron-deficient copper(III) corrole was utilized for the construction of donor-acceptor conjugates with zinc(II) porphyrin (ZnP) as a singlet excited state electron donor, and the occurrence of photoinduced charge separation was demonstrated by using transient pump-probe spectroscopic techniques. In these conjugates, the number of copper corrole units was varied from 1 to 2 or 4 units while maintaining a single ZnP entity to observe the effect of corrole multiplicity in facilitating the charge-separation process. The conjugates and control compounds were electrochemically and spectroelectrochemically characterized. Computational studies revealed ground state geometries of the compounds and the electron-deficient nature of the copper(III) corrole. An energy level diagram was established to predict the photochemical events by using optical, emission, electrochemical, and computational data. The occurrence of charge separation from singlet excited zinc porphyrin and charge recombination to yield directly the ground state species were evident from the diagram. Femtosecond transient absorption spectroscopy studies provided spectral evidence of charge separation in the form of the zinc porphyrin radical cation and copper(II) corrole species as products. Rates of charge separation in the conjugates were found to be of the order of 10(10)  s(-1) and increased with increasing multiplicity of copper(III) corrole entities. The present study demonstrates the importance of copper(III) corrole as an electron acceptor in building model photosynthetic systems.
authors.affiliation: International Center for Young Scientist (ICYS), National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki, 305-0044, Japan. NGO.Huynhthien@nims.go.jp.|WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki, 305-0044 (Japan. NGO.Huynhthien@nims.go.jp.
authors.forename: Thien H
authors.initials: TH
authors.lastname: Ngo
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Zieba
authors.affiliation: Department of Chemistry, University of North Texas, 1155 Union Circle, 305070, Denton, TX, 76203, USA.
authors.forename: Whitney A
authors.initials: WA
authors.lastname: Webre
authors.affiliation: Department of Chemistry, University of North Texas, 1155 Union Circle, 305070, Denton, TX, 76203, USA.
authors.forename: Gary N
authors.initials: GN
authors.lastname: Lim
authors.affiliation: Department of Physical Sciences and Mathematics, Wayne State College, 111 Main Street, Wayne, NE, 68787, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Karr
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.
authors.forename: Scheghajegh
authors.initials: S
authors.lastname: Kord
authors.affiliation: WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki, 305-0044 (Japan.
authors.forename: Shangbin
authors.initials: S
authors.lastname: Jin
authors.affiliation: WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki, 305-0044 (Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Ariga
authors.affiliation: Department of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
authors.forename: Marzia
authors.initials: M
authors.lastname: Galli
authors.affiliation: Department of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
authors.forename: Steve
authors.initials: S
authors.lastname: Goldup
authors.affiliation: WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki, 305-0044 (Japan. Jonathan.Hill@nims.go.jp.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Hill
authors.affiliation: Department of Chemistry, University of North Texas, 1155 Union Circle, 305070, Denton, TX, 76203, USA. Francis.Dsouza@unt.edu.
authors.forename: Francis
authors.initials: F
authors.lastname: D'Souza
keywords: copper(III) corroles; electron transfer; porphyrins; supramolecular chemistry