Synthesis and crystal and molecular structure of di-μ-(N-methylpiperidinium-4-thiolate)-bis[dichlorozinc(II)] monohydrate

The reaction of zinc chloride with 4-mercapto-N-methylpiperidinium chloride in aqueous solution gives the title complex. Crystals of the compound are monoclinic, space group P21/m, with a = 10.988(12), b = 13.086(12), c = 7.476(9) Å, β = 91.99(1)°. With Z = 2, the calculated density is 1.71 g cm-3 (measured density 1.69 g cm-3). Solution of the structure by direct methods led to a final weighted R factor of 0.072 for 2 028 independent reflections. The crystal structure of the zwitterionic complex consists of discrete dimeric molecules. Each sulphur atom of the ligand acts as a bridge between two zinc atoms. The crystallographic mirror plane passing through the zinc and chlorine atoms imposes a Cs symmetry on the molecule. The average Zn-Cl bond distance is 2.255(7) Å, while the Zn-S bond distances average 2.371(11) Å. The piperidine rings shows the usual 'chair' configuration. The dimeric molecules are bridged by a network of hydrogen bonds involving-NH groups and the chlorine atoms.