Separation or combination of non-covalently linked partners provides polymorphs of N-(aryl)-2-(propan-2-ylidene)hydrazine carbothioamides

Two polymorphs of N-(2-methoxyphenyl)-2-(propan-2ylidene) hydrazine carbothioamide have R-2(2)(8)-type hydrogen-bonded homo-dimers formed by N-H center dot center dot center dot S interactions. The difference between the two polymorphs originated due to weak C-(sp3)-H center dot center dot center dot S interactions in their respective self-assemblies. Also, three polymorphs of N-(4-nitrophenyl)-2-(propan-2ylidene)hydrazine carbothioamide were characterised by diffraction and spectroscopic techniques. One of the polymorphs out of the three polymorphs of N-(4-nitrophenyl)-2-(propan-2ylidene)hydrazine carbothioamide has two symmetry non-equivalent molecules in a unit cell. These symmetry non-equivalent molecules exhibited two independent self-assemblies in the lattice. One set of symmetry-independent molecules formed a zig-zag chain assisted by C-H center dot center dot center dot S interactions and possessed R-1(2)(11) hydrogen-bonded units; the other set of symmetry-independent molecules consisted of R-2(2)(8)-type N-H center dot center dot center dot S-bonded cyclic homo-dimers. The other two polymorphs comprised independent assemblies of these components. One polymorph was composed of R-2(2)(8) homo-dimers without C-(sp3)-H center dot center dot center dot S interactions, whereas the third polymorph consisted of R-1(2)(11) hydrogen-bonded units with bifurcated C-H center dot center dot center dot S bonds. The bifurcated hydrogen bond of the third polymorph possessed a sulphur atom as the pivot with an angle similar to 133.9 degrees, which was a relatively large bite angle for a bifurcated hydrogen bond. The characteristic spectroscopic and thermal features of all the polymorphs were presented. In this class of compounds, the hydrogen bond hierarchy may be avoided by a complementary effect of lower hierarchical interactions.