Crystal structure of pyridinium tetraisothiocyanatodipyridinechromium(III) pyridine monosolvate

Abstract

In the crystal structure of the title compound, (C5H6N)[Cr(NCS)4(C5H5N)2]·C5H5N, the CrIII ions are octahedrally coordinated by four N-bonding thiocyanate anions and two pyridine ligands into discrete negatively charged complexes, with the CrIII ion, as well as the two pyridine ligands, located on crystallographic mirror planes. The mean planes of the two pyridine ligands are rotated with respect to each other by 90°. Charge balance is achieved by one protonated pyridine molecule that is hydrogen bonded to one additional pyridine solvent molecule, with both located on crystallographic mirror planes and again rotated by exactly 90°. The pyridinium H atom was refined as disordered between both pyridine N atoms in a 70:30 ratio, leading to a linear N—H...N hydrogen bond. In the crystal, discrete complexes are linked by weak C—H...S hydrogen bonds into chains that are connected by additional C—H...S hydrogen bonding via the pyridinium cations and solvent molecules into layers and finally into a three-dimensional network.