Thioacetate complexes of Group 12 metals. Structures of Ph_4PZn(SC{O}Me)_3(H_2O) and Ph_4PCd(SC{O}Me)_3

摘要

The compounds Ph_4PZn(SC{O}Me)_3(H_2O) 1 and Ph_4PM(SC{O}Me)_3 (M = Cd 2 or Hg 3) were synthesized by treating the appropriate metal salt with Et_3NH~+MeC{O}S~- and Ph_4PCl 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 and Zn is bonded to sulfur atoms of three thioacetate ligands and an oxygen atom of the H_2O molecule to have an idealised tetrahedral geometry. The hydrogen atoms of the co-ordinated H_2O 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 CdS_3 kernel. The anion is best described as having fac octahedral geometry with an approximate C_3 symmetry. Metal NMR data have been measured for 2 and 3. The reduced temperature cadmium-113 NMR spectrum of a Cd(SC{O}Ph)_3~- mixture provides evidence for Cd(SC{O}Me)_x -(SC{O}Ph)_(3-x)~-(X = 3-0), confirming the intergrity of the two parent complexes in solution. Cadmium-113 NMR spectra of 2:L mixtures (L = H_2O, 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 H_2O, 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 H_2O varies with M in the order Zn~(II)>Cd~(II)>Hg~(II).