Solvothermal syntheses and characterization of thiostannates [M(en)3]2Sn2S6 (M = Mn, Co, Zn), the influence of metal ions on the crystal structure

Three new thiostannates [M(en)(3)](2)Sn2S6 (en = ethylenediamine, M = Mn(1), Co(2) and Zn(3)) were synthesized by solvo-thermal method. The crystals were grown up in a Teflon-lined steel autoclave at temperature about 180 degreesC. All the three compounds consist of discrete [Sn2S6](4-) anions, which are dimer of two tetrahedral SnS4 sharing a common edge. The transition metal cations are six-coordinated by three ethylenediamine molecules forming octahedral complex ions. Although the synthetic procedures, the mole ratio of the reactants and the solvent are essentially the same, the compound of Mn-II is quite different in structure from that of compounds of Co-II and Zn-II. Compound 1 crystallizes in monoclinic crystal system, C2/c, whereas compounds 2 and 3 crystallize in the orthorhombic crystal system, Pbca. Unlike compound 1, the [M(en)(3)](2+) cations in 2 and 3 are disordered. The difference of molecular packing between 1 and 2 - 3 is considered due to the influence of the entities of the metal ions, such as radii and the coordination properties. The thermal chemical behaviors of the compounds I - 3 were discussed and the results are also related to the property of the metal ions.