Voltammetric behaviour of uranyl-diethyldithiocarbamate complexes in aprotic medium

Abstract

The polarographic investigation of the reaction between uranyl and diethyldithiocarbamate ions in DMSO evidentiates two prevailing complex species: UO 2(DEDTC) + and UO 2(DEDTC) − 3. The two species exhibit one reversible cathodic wave (E 1 2 = −0.662V and −1.170V, respectively) both involving the reaction of the uranyl complex to uranium(V) complex. The formation of one reversible well-shaped anodic wave in the presence of diethyldithiocarbamate ion, due to the formation of mercury(II) complexes, has been already reported; in the present case, however, also the UO 2(DEDTC) − 3 species gives an anodic wave associated with the following electrode process: ▪ Cyclic voltammetric tests suggest that the mentioned cathodic processes are to be considered quasi-reversible, while the anodic one, involving the ligand exchange between UO 2+ 2 and Hg 2+, is not reversible. The stability constants of UO 2+ 2 and Hg 2+, diethyldithiocarbamate complexes are also estimated.