Solid-state structure of 1-(diaminomethylene)thiouron-1-ium propionate

Abstract

The single crystals of 1-(diaminomethylene)thiouron-1-ium propionate suitable for the X-ray analysis were grown using a solution growth technique room temperature. The compound crystallises in the centrosymmetric C2/c space group of the monoclinic system. The conformation of the 1-(diaminomethylene)thiouron-1-ium cation is not strictly planar, but slightly twisted. Both planar arms of the cation are oppositely rotated by 2.1(1)° around the CN bonds involving the central N atom. The propionate(−) anion is also non-planar, the carboxylate group is turned by 4.3(1)° in relation to the planar carbon chain. The arrangement of oppositely charged components, i.e. 1-(diaminomethylene)thiouron-1-ium cations and propionate(−) anions in the crystal is mainly determined by ionic and NH⋯O hydrogen bonding interactions forming two-dimensional network aligned to (100) plane. The neighbouring 2D layers interact via much weaker NH⋯S hydrogen bonds forming three-dimensional hydrogen bonded network. Hirshfeld surface and the analysis of 2D fingerprint plots are illustrating both quantitatively and qualitatively interactions governing the supramolecular assemblies. The compound was also characterised by the FT-IR and Raman spectroscopy. The vibrational assignments have been supported by the isotopic frequency shift.