Supramolecular hydrogen-bonding networks in the 1-(diaminomethylenene)thiouron-1-ium 4-hydroxybenzoate, 3,4-dihydroxybenzoate and 3,4,5-trihydroxybenzoate monohydrate crystals

Three crystals of 1-(diaminomethylene)thiouron-1-ium 4-hydroxybenzoate (1), 1-(diaminomethylene)thiouron-1-ium 3,4-dihydroxybenzoate (2) and 1-(diaminomethylene)thiouron-1-ium 3,4,5-trihydroxybenzoate monohydrate (3) were grown using a solution growth technique. The conformation of the 1-(diaminomethylene)thiouron-1-ium cation in these structures is very similar and exhibits twisting conformation. The planar COO− group of the oppositely charged components of the crystals, i.e. 4-hydroxybenzoate, 3,4-dihydroxybenzoate and 3,4,5-trihydroxybenzoate, are slightly inclined to the benzene ring. Both oppositely charged units, i.e. the 1-(diaminomethylene)thiouron-1-ium cation and respective mono- di- or trihydroxybenzoate anions, interact via R22(8) hydrogen bonding motif forming 1:1 supramolecular complexes. These supramolecular complexes interact each other via NO or OH⋯O hydrogen bonds forming the 3D-hydrogen bonding networks. These compounds were also characterised by the IR-spectroscopy. The characteristic bands of the NH2, OH, CS, COO− as well as of the skeletal groups are discussed.