The oxidation of dithiocarbamato complexes of nickel, copper and zinc

Abstract

Oxidation of N, N-di-n-butyldithiocarbamato (buzdtc) complexes of Cum, NiOI), ZnOI), Cd(I1) and Hg(II) is reported. Oxidation of Ni(bu2dtc)z with Clz, Brz, or of NiXz (X = CI, Br, Nos) with N,N,N',N'-tetra-n-butylthiuram disulfide (burtds) gives complexes of composition mi(buzdtc)3]X. These compounds are diamagnetic and dissolve in nitrobenzene as 1 : 1 electrolytes, their W spectra resemble that of the iso-electronic Co(buzdtc)s. The experimental data are in accord witli the assumption that in these compounds N i O (low spin d6) is surrounded by 6 S atoms in octahedral symmetry. The analogous selenium compound tris(N, N-di-n-butyldiselenocarbamato) nickelQV) bromide, having the same properties as the thio compounds, can also be prepared. Oxidation of Cu(buzdtc) with Clz or Brz yields paramagnetic products with the composition CuXa(buzdtc), in which Cu also has the formal oxidation number + 4, but the structure of these compounds is still obscure. Oxidation of Zn(buzdtc)z and the corresponding Cd and Hg compounds yields products, the analysis of which suggests the composition MXz(buzdtc)z (M = Zn, Cd or Hg, X = Br or I), but infrared studies indicate that the dithiocarbamato ligands of the starting substances are oxidized to buctds, which in the reaction products is coordinated to the metal in its normal oxidation state + 2.

Crystal and molecular structure of diiodo-N,N,N?,N?-tetramethylthiuramdisulphidemercury(II)

“…The observed C-N distances are n o t conclusive with respect to the increase o f the C-N bond order as indicated by infrared and nm r measurements. T he difference in the C-S distances agree w ith the infrared spectra (Brinkhoff et al, 1970). …”

“…In preceding papers, the preparations and properties o f diiodo-N ,N ,N ',N '-tetrabutylthiuram disulphidem ercury(II) (Brinkhoff et al, 1969) and o f the analogous ethyl derivative (Brinkhoff et al 1970) were reported. T he proposed m olecular structure was confirmed by an X -ray analysis o f the analogous methyl derivative, H gI2(M e4tds).…”

Metal-dithiocarbamate complexes: chemistry and biological activity

“…Indeed addition of halogens results in ligand-centered oxidation to give tetrahedral thiuram disulfide complexes [ZnX 2 {R 2 CN(S)S-SC(S)NR 2 }] resulting from sulfur-sulfur bond formation (eqn. 16) [57]. The thiuram disulfide here is only weakly bound and can readily be displaced and thus could potentially be released in a biological system under oxidizing conditions.…”

Metal complexes with two different sulfur containing ligands—II

“…In this group of bis(dtc) complexes only the copper compounds showed a reversible behaviour. This is reflected in a remarkable way in the preparative oxidation of dtc complexes, only the copper complex giving a reaction product of the same stoichiometry C u (dtc)2+, nickel [10], palladium and platinum[ll] giving tris-complexes, M (dtc)3+, with the metal in the oxidation state +4.…”