Crystal structure of dipotassium N-carbodi-thio-ato-l-prolinate trihydrate.

The mol-ecular and crystal structure of the l-proline-derived di-thio-carbamate-carboxyl-ate compound poly[tri-μ-aqua-(μ-2-carboxyl-atopyrrolidine-1-carbodi-thio-ato)dipotassium], [K2(C6H7NO2S2)(H2O)3] n or K2(SSC-NC4H7-COO)·3H2O, has been determined. The di-thio-carbamate moiety displays a unique coordination mode, comprising a 'side-on' π-coordinated K+ cation besides a commonly σ-chelated K+ cation. By bridging coordination of the CSS group, COO group and water mol-ecules, the K+ cations are linked into a two-dimensional coordination polymer extending parallel to the ab plane. These layers are again inter-connected by O-H⋯S hydrogen bonds.