In situ Formation of Thermally Stable, Room-Temperature Ionic liquids from CS2 and Amidine/Amine Mixtures

Amidinium dithiocarbamates salts with diverse structures are prepared in situ by adding one equivalent of CS, to an equimolar mixture of two nonionic molecules, an amidine and an amine. Many of the salts made in this way are room temperature ionic liquids (RTILs) and the others (ILs) melt well below the decomposition temperature of the salts, ca. 80 degrees C. Unlike the analogous amidinium carbamate RTILs, which are made by adding CO2 to amidine/amine mixtures and decompose near 50 C, the amidinium dithiocarbamates do not revert to their amidine/amine mixtures when they are heated. The thermal, rheological, conductance, and spectroscopic properties of representative examples from a total of 50 of these ILs and RTILs are reported, comparisons between them and their nonionic phases (as well as with their amidinium carbamates analogues) are made, and the thermolysis pathways of the ammonium dithiocarbamates are investigated.