Copper(I) and copper(III) diselenocarbamates

Abstract

(Received 13 J ~ e 1~2) It is known that the reaction of thiuram disulfide with excess of copper powder yields the copper(I)dithiocarbamate tetramer, [Cu(S2CNEt2)]4(I ). Due to the non-existence of the analogous selenuram diselenide (2) the reaction of copper with a mixture of selenuram monoand triselenide, (Et2NCSe)2Se and (Et2NCSe)2Se], was carried out. In this way copper(I) N,Ndiethyldiselenocarbamate, Cu(Se2CNEt2) , was obtained as a diamagnetic yellow complex, stable in dry air. The preparation however, has to be carried out in an inert atmosphere, for this copper(I) complex is easily oxidized. When the yellow solution of copper(I) diselenocarbamate in dichloromethane is exposed to air, this darkens rapidly and in the ultra-violet absorption spectrum band maxima appearwhich can be ascribed to the copper(II) bis(N,N-diethyldiselenocarbamate). A molecular weight determination (osmometric method: found 307, calc~. 306) revealed Cu(Se2CNEt2) to be monomeric in benzene solutions, which is in contrast with the reported (I) polymeric character of the analogous sulfur compounds [Cu(S2CNR2)] n (n = 2.9-4.6, in various solvents).