Abstract
Ionic liquids (ILs) are able to activate elements that are insoluble in common solvents. Here, the synthesis of binary antimony compounds directly from elements was explored. The 12 elements Ti-Cu, Al, Ga, In, and Te, known to form binary compounds with Sb, were reacted with Sb in [P-66614]Cl under inert conditions in a closed glass flask with vigorous stirring for 16 h at 200 degrees C. This was immediately successful in four cases and resulted in the formation of NiSb, InSb, Cu2Sb and Sb2Te3. The applied reaction temperature is several hundred degrees below the temperatures required for solvent-free conversions. Compared to reactions based on diffusion in the solid state, reaction times are much shorter. The IL is not consumed and can be recycled. Since the reaction with Cu showed almost complete conversion, the influences of reaction time, temperature and medium were further investigated. Among the tested imidazolium ILs ([BMIm]Cl, [BMIm][OAc], [BDMIm]Cl) and phosphonium ILs ([P-66614]X, X=Cl-, [DCA](-), [OAc](-), [NTf2](-)), those with chloride anion yielded the best results. In a diffusion experiment, Cu2Sb formed on the copper, which indicates that antimony forms mobile species in these ILs. Supplemental crystal structure data of (As3S4)[AlCl4], which was ionothermally synthesized from As and S, are reported.
