Journal
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
Volume -, Issue 32, Pages 4850-4859Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/ejic.200900673
Keywords
Electron transfer; Donor-acceptor systems; Time-resolved spectroscopy; Iridium; Photochemistry
Categories
Funding
- Swiss National Science Foundation [PP002-110611]
- Swiss State Secretariat for Education and Research [C07.0063]
Ask authors/readers for more resources
Six cyclometalated iridium(III) complexes were investigated to assess their potential as photosensitizers for long-range electron transfer, and two of them were incorporated directly into covalent donor-bridge-acceptor molecules. The influence of ligand substitutions on the excited-state properties and the photoredox behavior of the iridium complexes was explored by optical absorption, steady-state and time-resolved luminescence spectroscopy, as well as by electrochemical methods. Bimolecular electron transfer between the photoexcited complexes and 10-inethylphenothiazine and methylviologen was found to be only weakly dependent on the ligand substitutions. Intramolecular long-range electron transfer from phenothiazine to photoexcited iridium(III) in the dyads is slow due to the occurrence of a Coulomb barrier. Consequently, an electron-transfer photoproduct is only observable in the transient absorption spectrum of a donor-bridge-acceptor molecule with a fluorinated photosensitizer that exhibits a very long excited-state lifetime. A flash-quench technique is necessary for detection of an electron-transfer product in the dyad with a non-fluorinated photosensitizer. The occurrence of a Coulomb barrier associated with intramolecular (excited-state) long-range electron transfer in the dyads with cyclometalated iridium(III) photosensitizers represents an important difference to previously investigated similar donor-bridge-acceptor molecules with photosensitizers based on d(6) metal diimine complexes. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available