Alkali metal dithiocarbamato carboxylates (DTCCs) : synthesis, properties, and crystal structures

Abstract

A series of alkali metal salts of dithiocarbamate-substituted carboxylate (DTCC) anions were prepared by reaction of the parent amino acids with carbon disulfide and an alkali metal hydroxide. The target compounds, which were isolated in anhydrous form or as hydrates, were extensively characterized by elemental analyses, IR and NMR spectroscopy, thermal analyses, cyclic voltammetry, and single-crystal X-ray diffraction. The isolated compounds are more or less hygroscopic and display a varying dehydratization and decomposition behavior upon heating. The assumed degradation of the DTCC scaffold was found to depend on the substitution pattern as well as on the alkali metal counterion, and covers a range between 200 and 340°C. In aqueous solution, the DTCC anions show irreversible electrochemical oxidations, where the corresponding redox potentials are governed by the substitution pattern of the nitrogen atom. Single-crystal structural analyses of sodium and potassium derivatives revealed that these compounds exist as two- or three-dimensional coordination polymers in the solid state, with the alkali-metal ions adopting typical irregular coordination environments with coordination numbers of six or higher.