Photoreactions of p-Quinones with Dimethyl Sulfide and Dimethyl Sulfoxide in Aqueous Acetonitrile

Authors

  • Helmut Görner

    Corresponding author
    1. Max-Planck-Institut für Bioanorganische Chemie, D-45413 Mülheim an der Ruhr, Germany
    • To whom correspondence should be addressed: Max-Planck-Institut für Bioanorganische Chemie, D-45413 Mülheim an der Ruhr, Germany. Fax: 49 208 306 3951; e-mail: goerner@mpi-muelheim.mpg.de

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  • This paper is part of a special issue dedicated to Professor J. C. (Tito) Scaiano on the occasion of his 60th birthday.

ABSTRACT

The effects of dimethyl sulfide (DMS) and dimethyl sulfoxide (DMSO) on the photoreactions of 1,4-benzoquinone (BQ), 1,4-naphthoquinone (NQ), 9,10-anthraquinone (AQ) and several derivatives in acetonitrile/water were studied. The observed triplet state of the quinones is quenched and the rate constant is close to the diffusion-controlled limit for reactions of most quinones with DMS and lower with DMSO. Semiquinone radical anions (Q*-) produced by electron transfer from sulfur to the triplet quinone were detected. For both DMS and DMSO the yield of Q*- is similar, being generally low for BQ and NQ, substantial for AQ and largest for chloranil. The specific quencher concentrations and the effects of quinone structure and redox potentials on the time-resolved photochemical properties are discussed.

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