Crystal structures of two hydrazinecarbothioamide derivatives: (E)-N-ethyl-2-[(4-oxo-4H-chromen-3-yl)methylidene]hydrazinecarbothioamide hemihydrate and (E)-2-[(4-chloro-2H-chromen-3-yl)methylidene]-N-phenylhydrazinecarbothioamide

The title compounds, C₁₃H₁₃N₃O₂S·0.5H₂O, (I), and C₁₇H₁₄ClN₃OS, (II), are hydrazinecarbothioamide derivatives. Compound (I) crystallizes with two independent molecules (AandB) and a water molecule of crystallization in the asymmetric unit. The chromene moiety is essentially planar in moleculesAandB, with maximum deviations of 0.028 (3) and 0.016 (3) Å, respectively, for the carbonyl C atoms. In (II), the pyran ring of the chromene moiety adopts a screw-boat conformation and the phenyl ring is inclined by 61.18 (9)° to its mean plane. In the crystal of (I), bifurcated N—H...O and C—H...O hydrogen bonds link the two independent molecules formingA–Bdimers with twoR₂¹(6) ring motifs, andR₂²(10) andR₂²(14) ring motifs. In addition to these, the water molecule forms tetrafurcated hydrogen bonds which alternately generateR₄⁴(12) andR₆⁶(22) graph-set ring motifs. There are also π–π [inter-centroid distances = 3.5648 (14) and 3.6825 (15) Å] interactions present, leading to the formation of columns along thec-axis direction. In the crystal of (II), molecules are linked by pairs of N—H...S hydrogen bonds, forming inversion dimers with anR₂²(8) ring motif. The dimers are linked by C—H...π interactions, forming ribbons lying parallel to (210).