Volume 155, 2012

Formation of a long-lived electron-transfer state of a naphthalene–quinolinium ion dyad and the π-dimer radical cation

Abstract

An electron donor–quinolinium ion dyad, 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh+–NA), has been synthesized based on a rational design. The X-ray crystal structure of QuPh+–NA indicates that the dihedral angle between the NA and QuPh+ moieties of QuPh+–NA is nearly perpendicular. The one-electron reduction potential (Ered) was observed as a well-defined reversible wave at −0.90 V versusSCE. The one-electron reduced species (QuPh˙–NA) was detected by ESR. The electron self-exchange rate constant (kex) between QuPh+–NA and QuPh˙–NA has been determined from the ESR linewidth alternation. The reorganization energy (λ) of the electron self-exchange was determined to be 0.42 eV from the kex value. Femtosecond laser irradiation of QuPh+–NA at 355 nm results in formation of the ET state (QuPh˙–NA˙+) within 0.5 ps via photoinduced ET from NA to the singlet-excited state of QuPh+. The transient absorption bands at 420 nm and 700 nm are assigned to the QuPh˙ and NA˙+ moieties, respectively. The nanosecond laser excitation of QuPh+–NA affords the broad absorption band at 1000 nm and is due to the π-dimer radical cation formed between QuPh˙–NA˙+ and QuPh+–NA. The intramolecular back electron-transfer process was too slow to compete with the intermolecular back electron-transfer reaction judging from the decay time profile of QuPh˙–NA˙+, which obeyed second-order kinetics.

Supplementary files

Article information

Article type
Paper
Submitted
27 Apr 2011
Accepted
01 Jun 2011
First published
06 Jul 2011

Faraday Discuss., 2012,155, 89-102

Formation of a long-lived electron-transfer state of a naphthalene–quinolinium ion dyad and the π-dimer radical cation

H. Kotani, K. Ohkubo and S. Fukuzumi, Faraday Discuss., 2012, 155, 89 DOI: 10.1039/C1FD00084E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements