Chromatographic study of the reaction of mercury(II) and silver(I) ions with nickel dithiocarbamate complexes derived from some aromatic amine drugs

When nickel dithiocarbamate complexes derived from aromatic amines were reacted with mercury(II) or silver(I) ions, they did not undergo the expected simple exchange reaction wherein the corresponding mercury or silver complexes are formed. Instead, these ions caused the precipitation of sulphur, which facilitated the formation of non-chelating compounds. When a β-hydroxyl group was present in the aromatic amine ligand, a cyclic oxazolidine compound was formed; absence of the β-hydroxyl group led to the formation of isothiocyanate compounds. For example, reaction of mercury or silver with the nickel dithiocarbamate complexes derived from (±)-ephedrine and (±)-pseudoephedrine gave isomers of 5-phenyl-3,4-dimethyloxazolidine-2-thione, whereas the complex derived from (±)-amphetamine produced amphetamine isothiocyanate. The retention behaviour of these compounds was studied using high-performance liquid chromatography and gas chromatography and their structures were elucidated using chemical ionization mass spectrometry and proton nuclear magnetic resonance spectroscopy