M. Julliard, M. Chanon
Aug 1, 1986
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0
Influential Citations
6
Citations
Journal
Journal of Photochemistry
Abstract
Abstract The reactions between 4-bromobenzophenone, 4-haloacetophenones and phenylthiolate in acetonitrile, dimethyl sulphoxide and dimethyl formamide were quantitatively studied under photostimulation. Results complementing those obtained by electrochemical methods were obtained. Besides the substitution product the reduction product (3%) and diphenyl disulphide (10% – 20%) are formed. The S RN 1 mechanism of this reaction was confirmed by an overall quantum yield of greater than unity and through quenching studies using 1,4-benzoquinone or tetracyanoquinodimethane. The initial overall quantum yield was related linearly to I 1 2 and to the nucleophile concentration, suggesting quadratic termination steps. Competitive experiments between 4-haloacetophenones confirmed the previously reported order of reactivity Br > Cl > F. From a synthetic point of view, the electrochemical process has a slight advantage because of byproduct recycling.