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

Abstract

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 C_s 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.