Growth, single crystal investigation and physico-chemical properties of thiocyanate coordination compounds based on 1,4-dimethylpiperazine

Four new hybrid organic-inorganic compounds based on 1,4-cimethylpiperazinium, [C6H16N2M(SCN)4]·2H2O (M = Co(1), Ni(2)), [(C6H16N2)Cd(SCN)4] (3), and [C6H16N2(SCN)2] (4), were prepared by the evaporation crystal growth method at room temperature. These complexes were characterized by their X-ray crystal structure; spectroscopic methods such as FTIR analysis supported the presence of surface ligand groups of thiocyanates and identified the vibrational absorption bands. The piperazinium ring adopts a slightly distorted chair conformation which is more stable because it does not have any steric hindrance or steric repulsion between the hydrogen bonds and which favors the entities coordination. Intermolecular interactions were investigated by Hirshfeld surfaces and contact enrichment tools. In the crystals, extensive intermolecular interactions have been used in the self-assembly of motifs, including strong H-bonds. The components are linked mainly by N-H…S, O-H…S, and N-H…N hydrogen-bonding interactions, resulting in a three-dimensional network. The arrangements of the anions and cations in the solids are governed not only by the size and symmetry of the cations, but also by the non-covalent bonds in the crystal structures.