Two-dimensional hydrogen-bonded networks in 1-(diaminomethylene)thiouron-1-ium nitrate and bis[1-(diaminomethylene)thiouron-1-ium] phosphonate monohydrate

Abstract

Crystals of the title compounds, C2H7N4S+·NO3−, (I), and 2C2H7N4S+·HPO32−·H2O, (II), are built up from 1-(diaminomethylene)thiouron-1-ium cations and nitrate anions in (I), and from phosphonate anions and water molecules in (II). In both crystals, the cations and anions are linked togetherviaN—H...O hydrogen bonds. The 1-(diaminomethylene)thiouron-1-ium cations exhibit a twisted conformation. Both arms of the cations are planar and are turned in opposite directions around the C—N bond involving the central N atom. Hydrogen-bonding interactions join oppositely charged units into layers in the nitrate salt and into double layers in the phosphonate monohydrate salt. In addition, the structures are stabilized by π–π interactions between the delocalized π bonds of the cations. The significance of this study lies in the illustration of the differences between the supramolecular aggregations in the nitrate and phosphonate salts of a small organic molecule. The different geometries of the counter-ions and their different potential for hydrogen-bond formation results in markedly different hydrogen-bond arrangements.