6-Chlorothieno[2,3-e]-1,4,2-dithiazine-3(2H)-thione-1,1-dioxide, Ammonium Salt Sesquihyrate: Synthesis, Crystal Structure and Density Functional Calculations

The title compound crystallizes in the monoclinic space group C2/c space group, with unit cell dimensions of a = 15.6684(3) A ? , b = 7.3974(2) A ? , c = 21. 2669(5) A ? ; b = 106.7770(10) (Z = 8). In the title compound, NH4 ?C5HClNO2S4 ?1.5 H2O, the 1,4,2-dithiazine ring adopts a distorted half-chair conformation. The structure displays several cooperative intermolecular N/O? HN/O/S hydrogen-bonding interactions, giving rise to a two-dimensional layers packing motif. The layers are built up from seven component entities formed via extensive intermolecular N/O?HN/O/S hydrogen bonds involving 6-chlorothieno[2,3-e]-1,4,2-dithiazine-3(2H)-thione-1, 1-dioxide anions, ammonium cations and water molecules. The geometry of the title compound was fully optimized using a Density functional B3LYP/6-31G(d) and B3LYP/ 6-31?G(d) methods and the results were consistent with experimental values. The binding energy and associated basis set superposition as well as the thermodynamic quantities were calculated.