On cobalt(II)N,N-diethyldithiocarbamate

Abstract

A recent article by D'Ascenzo and Wendlandt [1 ] in this journal describes the preparation and thermal properties of an N,N-diethyldithiocarbamate (Et2dtc) complex of cobalt(II), namely NaCo(Et2dtc)a. We were particularly interested in this complex since we have been trying for some time, so far without success, to synthesize diethyldithiocarbamate complexes of divalent first row transition metals (Cr-Zn(II) inclusive) of the type M(Et2dtc);-with alkali metal or tetraalkyl ammonium cations. We find this cobalt(II) complex even more significant in the light of a number of observations [2-4] that aqueous solutions of cobalt(II) are spontaneously oxidized to cobalt(III) in the presence of NaEt2dtc, even when oxygen is rigorously excluded [5].We therefore regarded the formulation of the product as NaCo(Et~dtc)z with some scepticism and repeated the experimental procedure [i ] for its preparation. From several different preparations we obtained the same dark green solid (m.p. 252-254~ which we therefore assume to be identical with the product obtained by D'Ascenzo and Wendlandt [I]. This corresponds in all respects to the well known [6] complex of cobalt(III), Co(Et2dtc)3. Thus, its solution (in methylene chloride) and reflectance spectrum which shows a band at 15.500 cm -1 (5 ,,, 600) and a shoulder at 20.800 cm -~ is in good agreement with the published [4] spectrum of Co(Et~dtc)a. The spectrum is also extremely similar to that of the complex Co($2COC2H5) 3, which can be made from cobalt(II) salts and potassium ethylxanthate [7]. The dithiocarbamate complex is strictly isomorphous with the black Fe(Et~dtc)a [8]. Its mass spectrum (direct inlet, 220~ 80 eV) shows very strong peaks at m/e 503, which is the base peak and which corresponds to the molecular ion Co(Et2dtc) +, and at 355 and 207 which correspond to the loss of one and two Et2dtc units respectively, together with a large number of smaller peaks below m/e 200. The metal analysis found by D'Ascenzo and Wendlandt of 11.3 is reasonably close to the value required for Co(Et2dtc)3 of 11.69 ~ particularly if the compounds were not completely free of water, or possibly, contaminated with small amounts of sodium chloride.We were also interested in the products listed as Ni(Et2dtc)z 9 6HaO and Cu(Etzdtc)2" 1.5H20. In the course of our studies [9] on reactions between metal(II) bipyridyl and o-phenanthroline salts and NaEt2dtc in aqueous solutions

Reactions of Sodium N,N-Diethyldithiocarbamate and Potassium Ethyl Xanthate with some 3d Transition Metal Halides in the presence of 2,2′-Bipyridyl and 1,10-Phenanthroline

“…Thus, it is apparent that the reduction of either Cu2+ or CubipyZ2+ by Xan-is thermodynam- Reactions between the metal halides, base, and xanthate in 1 :3:2 mole ratios give different products which will be described in a later publication (22).…”

“…It is interesting that one adducts of NiXan, including NiXan,.bipy and tris(xanthate) complex, (R,N)NiXan,, has been NiXan,.phen have been studied particularly characterized (4)(5)(6) while in the dithiocarbamate regarding the assignment of infrared vibrations. series the formulation (7) of a complex as With dithiocarbamates, Codtc,.phen has been Na[Codtc,] has been questioned (8), and there synthesized (13) For personal use only.…”

Electrochemical reduction and oxidation of cobalt(III) dithiocarbamates

“…The cobalt(IV) complex is therefore inherently unstable, and we have failed to isolate this species in the solid state. Dimer formation is well established in both solid state and solution chemistry for many dithiocarbamate complexes.5,6 It is of course possible that [Co(R2dtc)3]+ is in equilibrium with [Co2(R2dtc)6]2+ as is the case with the complex Os(R2dtc)3 where the reaction 2[Os(R2dtc)3]+ ^[Os2(R2dtc)6]2+ (14) has been well characterized.30 Alternatively, since a sevencoordinate complex of Co(IV) would be unexpected, the equilibrium reaction 2[Co(R2dtc)3]+ -[Co2(R2dtc)5]2+ + '^(thiuram disulfide) (15) could be consistent with the observed data. However, in all cases a cobalt(IV) species is implicated in the reaction pathway.…”

Coordination Chemistry of the Parent Dithiocarbamate H2NCS2–: Organometallic Chemistry and Tris-Chelates of Group 9 Metals

“…Dithiocarbamates are one important class of bidentate S,S-donor ligands with the general formula S 2 CNR 2 – . − Dialkyldithiocarbamates can be easily obtained by treating carbon disulfide with the corresponding secondary amine. − Complexes with dialkyldithiocarbamates have been extensively studied: complexes are known for every transition metal. − Among their general properties, good solubility in organic solvents, good thermal stability, − and vibrant colors are common characteristics. Some dithiocarbamate complexes with diethyldithiocarbamate have been reported to be volatile. , …”