Reactions of organic sulphur-sulphur bonds
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Rates of cleavage reactions of substituted diaryl disulphides have been measured in 60% aqueous t-butanol at 30.0°C using cyanide ion, sulphite ion and hydroxide ion as nucleophiles. Variations of substituents on the leaving group (thiophenoxide) gives results which correlate well with pK’s of the appropriate thiophenoxides. Variation of substituents on the aryl group attached to the sulphur atom whre the nucleophilic substitution is taking place gives very unusual sustituent effects. –R para groups have a decelerating effect and + para groups an accelerating effect on the rate of the reaction, even though the Hammett p (measured from the meta points) is positive. An explanation of these effects, involving participation of the d orbitals of the sulphur atom during a nucleophilic substitution, has been given.