Abstract
The title compound, 4-hydroxy-2
H
-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide-oxalohydrazide (1:1), is determined using X-ray diffraction techniques and the molecular structure is also optimized at the B3LYP/6-31G(
d,p
) level using density functional theory (DFT). The asymmetric unit consists of four independent molecules. The oxalohydrazide molecules have the centre of symmetry at the mid-point of the central C-C bond. Each thiazine ring adopts a
half-chair
conformation. Intermolecular C-H...O, N-H...O and N-H...N hydrogen bonds produce
R
2
2
(10),
R
2
2
(13),
R
3
3
(12) and
R
3
3
(15) rings, which lead to one-dimensional polymeric chains. An extensive three-dimensional supramolecular network of N-H...N, N-H...O, C-H...O and O-H...O hydrogen bonds is responsible for crystal structure stabilization.