Bis(piperazin-1-ium) tetrasulfidometalates: Solid state synthesis, thermal studies and structural characterization

Abstract

The organic tetrasulfidometalates (pipH)(2)[MS(4)] (pipH = piperazin-1-ium; M = W 1; M = Mo 2) were prepared by a mechanical grinding of solid (NH(4))(2)[MS(4)] (M = Mo or W) with the cyclic diamine piperazine (pip). Compounds 1 and 2 which contain the monoprotonated cation of piperazine were characterized by elemental analysis, infrared, Raman and UV-Vis spectra and their structures were determined. The title compounds decompose endothermically to carbon containing metal disulfide residues. Both compounds are isostructural and crystallize in the centrosymmetric triclinic space group P (1) over bar. The structures of both compounds consist of two crystallographically independent piperazin-1-ium cations and a tetra-sulfidometalate dianion, with all atoms situated in general positions. An intramolecular N-H...N interaction links the organic cations into pairs and the pairs thus formed extend into a one-dimensional chain of cations with the aid of an intermolecular N-H...N bond. The [MS(4)](2-) anions are linked to the chains of piperazin-1-ium cations via N-H...S and C-H...S interactions. A comparative study of the spectral, structural and thermal properties of the title compounds with those of the previously reported (pipH(2))[MS(4)] (pipH(2) = piperazinediium) compounds containing the (pipH(2))(2+) dication is described.