Thioacetate complexes of Group 12 metals. Structures of [Ph4P][Zn(SC{O}Me)3(H2O)] and [Ph4P][Cd(SC{O}Me)3]†

Abstract

The compounds [Ph₄P][Zn(SC{O}Me)₃(H₂O)] 1 and [Ph₄P][M(SC{O}Me)₃] (M = Cd 2 or Hg 3) were synthesized by treating the appropriate metal salt with Et₃NH⁺MeC{O}S^– and Ph₄PCl in the ratio 1∶3∶1 in water. The structures of 1 and 2 were determined by single crystal X-ray diffraction methods. In 1 the Zn is bonded to sulfur atoms of three thioacetate ligands and an oxygen atom of the H₂O molecule to have an idealised tetrahedral geometry. The hydrogen atoms of the co-ordinated H₂O molecule are involved in intramolecular O–H· · ·O hydrogen bonding with two carbonyl oxygen atoms. Approximate mirror symmetry is present in the anion. In the [Cd(SC{O}Me)₃]^– anion in 2 a propeller-like arrangement of the three co-ordinated MeC{O}S^– is found. The three sulfur atoms are strongly bound to Cd giving a pyramidal CdS₃ kernel. The anion is best described as having fac octahedral geometry with an approximate C₃ symmetry. Metal NMR data have been measured for 2 and 3. The reduced temperature cadmium-113 NMR spectrum of a [Cd(SC{O}Me)₃]^––[Cd(SC{O}Ph)₃]^– mixture provides evidence for [Cd(SC{O}Me)_x- (SC{O}Ph)_3–x]^– (x = 3–0), confirming the integrity of the two parent complexes in solution. Cadmium-113 NMR spectra of 2∶L mixtures (L = H₂O, DMF or DMSO) show that [Cd(SC{O}Me)₃]^– is a weak acceptor. Mercury-199 NMR spectra of analogous 3∶L mixtures show that [Hg(SC{O}Me)₃]^– has, at best, a weaker acceptor ability towards H₂O, DMF and DMSO than its cadmium analogue. The syntheses and metal NMR data show that the acceptor ability of [M(SC{O}Me)₃]^– (M = Zn to Hg) towards H₂O varies with M in the order Zn^II > Cd^II > Hg^II.