Synthesis and crystal structure studies of 5-(tri-fluoro-meth-yl)-1,3,4-thia-diazol-2(3)-one at 180 K.

The synthesis and crystal structure of CHFNOS, systematic name 5-(tri-fluoro-meth-yl)-1,3,4-thia-diazol-2(3)-one (5-TMD-2-one), a compound containing the pharmacologically important heterocycle 1,3,4-thia-diazole, is presented. The asymmetric unit comprises six independent mol-ecules (' = 6), all of which are planar. The r.m.s. deviations from each mean plane range from 0.0063 to 0.0381 Å, not including the CF fluorine atoms. Within the crystal, two of the mol-ecules form hydrogen-bonded dimers that in turn combine with inversion-related copies to form tetra-meric constructs. Similar tetra-mers, but lacking inversion symmetry, are formed by the remaining four mol-ecules. The tetra-mers are linked into tape-like motifs by S⋯O and O⋯O close contacts. The environments of each symmetry-independent mol-ecule were compared a Hirshfeld surface analysis. The most abundant atom-atom contacts are between fluorine atoms, while the strongest result from N-H⋯O hydrogen bonds.