Reversible hydration characteristics of Group VI tetrathiometalates derived from Tris(2-aminoethyl)amine

Abstract

The complexes (trenH2)[MoS4]·H2O 1 and (trenH2)[WS4]·H2O 2 (tren = tris(2-aminoethylamine) were synthesized by the base promoted cation exchange method. Both complexes can be dehydrated to the corresponding anhydrous compounds (trenH2)[MS4] (M = Mo 3; W 4) and the anhydrous complexes can be rehydrated. This reversible hydration behaviour has been investigated by isothermal weight loss studies, IR spectroscopy, TG-DTA studies and X-ray measurements. On heating, complexes 1 and 2 emit crystal water forming the corresponding anhydrous complexes 3 and 4. Equilibriation of the anhydrous complexes over aqueous ammonia, results in the formation of the monohydrates 1 and 2. The complexes 3 and 4 are isostructural as evidenced from the IR and X-ray studies. At elevated temperatures, all the tetrathiometallates decompose to yield carbon contaminated amorphous metal disulfides.