The complexes [cation] [Hg(SR)3](R = Me, cation = Et4N+; R = But, cation = Et4N+, Bu4N+, [N(Ph3P)2]+) have been prepared. The crystal structure of the methanethiolate complex shows that it contains centrosymmetric dinuclear anions [(MeS)2Hg(�-SMe)2Hg(SMe)2]2- with distorted tetrahedral geometry about the mercury atoms. Vibrational spectroscopic evidence suggests that this complex dissociates on dissolution in ethanol to give mononuclear [Hg(SMe)3]- species. The ButS- complexes appear to exist as mononuclear [Hg(SBut)3]- species both in the solid state and in solution. The metal-sulfur stretching frequencies are assigned for all of the complexes studied, and the vibrational spectra are discussed in terms of the structures of the complex anions involved. Crystal data for [(C2H5)4N]2Hg2(SCH3)6 : a 8.656(5), b gS130(6), c 12.368(8) �; α 102.16(4), β 105.51(4), γ 105.29(4)�; space group P1, Z 1, R 0.034, Rw 0.042.

Some rate constants for the reduction of para-substituted benzenediazonium ions by the radicals eaq-, ·CH2OH, (CH3)2·COH and some semiquinone radical anions have been measured. The substituent group has no effect on the rates with eaq-, but as the reduction potential of the reducing radical becomes more positive, the substituent effect increases, electron-withdrawing groups enhancing the rates. No free halide is formed on reduction of p-BrC6H4N2+ or p-IC6H4N2+ by eaq- or ·CH2OH.

Electron-withdrawing substituents are shown to increase the chain length of free-radical hydrodediazoniation reactions, but the actual reaction step causing the substituent effect depends on the relative rates of propagation and termination reactions. With benzyl alcohol as reducing agent the rate of the slow propagation step is increased, while with isopropyl alcohol the rate of the termination step is decreased. Rate constants for some reactions of radicals with diazonium ions are reported, and the nature of some of these reactions and their implication for an understanding of the homolysis of aromatic diazo compounds are discussed.

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Die Salze der Titelkomplexe (I) werden durch Metathesereaktionen aus den entsprechenden Dichloroauraten(I) und Thiolat‐ Ionen dargestellt (keine Ausb.‐Angaben).