American Chemical Society
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Chemistry of Thiobenzoates: Syntheses, Structures, and NMR Spectra of Salts of [M(SOCPh)3]- (M = Zn, Cd, Hg)

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journal contribution
posted on 1996-05-22, 00:00 authored by Jagadese J. Vittal, Philip A. W. Dean
The salts (Ph4E)[M(SOCPh)3] (M = Zn, Cd, or Hg; E = P or As) are produced by the reaction of Zn(NO3)2·6 H2O, Cd(NO3)2·4H2O or HgCl2 with Et3NH+PhCOS- and (Ph4E)X (E = P, X = Br; E = As, X = Cl) in aqueous MeOH in the ratios M(II):PhCOS-:Ph4E+ = 1:≥3:≥1. The crystal structures of (Ph4P)[Zn(SOCPh)3] (1), (Ph4As)[Cd(SOCPh)3] (2) and (Ph4P)[Hg(SOCPh)3] (3) have been determined by single-crystal X-ray diffraction experiments. Crystal data for 1:  triclinic; space group P1̄; Z = 2; a = 10.819(2) Å, b = 13.219(3) Å, c = 15.951(3) Å; α = 101.75(2)°, β = 97.92(1)°, γ = 109.18(2)°. Crystal data for 2:  triclinic; space group P1̄; Z = 2; a = 10.741(2) Å, b = 13.168(2) Å, c = 15.809(2) Å; α = 101.00(1)°, β = 97.65(1)°, γ = 109.88(1)°. Crystal data for 3:  monoclinic; space group P21/n; Z = 4; a = 13.302(2) Å, b = 14.276(2) Å, c = 21.108(2) Å; β = 90.92(1)°. The compounds 1 and 2 are isomorphous and isostructural. In the anions [M(SOCPh)3]- the metal atoms have trigonal planar coordination by three sulfur atoms. The metal atoms are further more weakly coordinated intramolecularly to one (M = Hg) or two (M = Zn, Cd) thiobenzoate oxygen atom(s). Using the Bond Valence approach it is found that the contribution of M···O bonding to the total bonding is in the order Cd > Zn > Hg. The metal (113Cd, 199Hg) NMR signals of [M(SOCPh)3]- (M = Cd, Hg) are more shielded than those found for MS3 kernels in thiolate complexes, a difference attributed to the M...O bonding in the thiobenzoate complexes. The 113Cd resonance of [Cd(SOCPh)3]- in dilute solution is in the region anticipated from dilution data for [Na(Cd{SOCPh}3)2]-.