Ethyl 2-[(2,4-difluoro­phen­yl)hydrazinyl­idene]-3-oxobutano­ate

The asymmetric unit of the title compound, C₁₂H₁₂F₂N₂O₃, contains two mol­ecules, both of which exist in an E conformation with respect to their C=N bonds [1.321 (6) and 1.310 (6) Å]. The mol­ecular conformations are supported by intra­molecular N—H...O hydrogen bonds, which generate S(6) rings. In the crystal, mol­ecules are linked by C—H...O and C—H...F hydrogen bonds into layers lying parallel to (001). The crystal studied was an inversion twin with a 0.58 (1):0.42 (1) domain ratio.

1-[2-(4-Chloro­phen­yl)-5-phenyl-2,3-dihydro-1,3,4-oxadiazol-3-yl]ethanone

In the title compound, C₁₆H₁₄ClN₃O₂, the 2,3-dihydro-1,3,4-oxadiazole ring [maximum deviation = 0.030 (1) Å] and the pyridine ring [maximum deviation = 0.012 (1) Å] are inclined slightly to one another, making a dihedral angle of 11.91 (5)°. The chloro-substituted phenyl ring is almost perpendicular to the 2,3-dihydro-1,3,4-oxadiazole and pyridine rings at dihedral angles of 86.86 (5) and 75.26 (5)°, respectively. In the crystal, π–π [centroid–centroid distance = 3.7311 (6) Å] and C—H...π inter­actions are observed.

N′-(3,4-Dichloro­benzyl­idene)-5-methyl-1-(4-nitro­phen­yl)-1H-1,2,3-triazole-4-carbohydrazide

In the title compound, C₁₇H₁₂Cl₂N₆O₃, the 1H-1,2,3-triazole ring [maximum deviation = 0.003 (1) Å] forms dihedral angles of 34.08 (6) and 28.38 (6)°, respectively, with the nitro- and dichloro-substituted benzene rings. The dihedral angle between the benzene rings is 6.68 (5)°. In the crystal, C—H...O hydrogen bonds link the mol­ecules into chains running parallel to the a axis.

3-(1-Benzofuran-2-yl)-1H-1,2,4-triazole-5(4H)-thione monohydrate

In the title hydrate, C₁₀H₇N₃OS·H₂O, the essentially planar benzofuran [maximum deviation = 0.006 (1) Å] and 4,5-dihydro-1H-1,2,4-triazole [maximum deviation = 0.007 (1) Å] rings form a dihedral angle of 11.67 (6)°. In the crystal, O—H...N, O—H...S, N—H...O and N—H...S hydrogen bonds link the mol­ecules into sheets lying parallel to the bc plane. Aromatic π–π stacking inter­actions [centroid–centroid distances = 3.5078 (8)–3.6113 (8) Å] are also observed.

4-Bromo­acetyl-3-phenyl­sydnone

In the title compound (systematic name: 4-bromoacetyl-1,2,3-oxadiazol-3-ylium-5-olate), C₁₀H₇BrN₂O₃, the 1,2,3-oxadiazole ring and bromo­acetyl group are essentially planar [maximum deviation = 0.010 (4) and 0.013 (3) Å respectively] and form dihedral angles of 59.31 (19) and 67.96 (11)°, respectively, with the phenyl ring. The 1,2,3-oxadiazole ring is twisted slightly from the mean plane of the bromo­acetyl group, forming a dihedral angle of 9.16 (24)°. In the crystal, mol­ecules are linked by pairs of weak C—H...O hydrogen bonds into inversion dimers with R₂²(12) ring motifs. The dimers are further connected by weak C—H...O hydrogen bonds into an infinite tape parallel to the b axis. In addition, π–π stacking inter­actions [centroid–centroid distance = 3.6569 (19) Å] and short inter­molecular contacts [O...O = 2.827 (3) and C...C = 3.088 (5) Å] are observed.

N′-[(E)-4-Bromo­benzyl­idene]-1-benzofuran-2-carbohydrazide monohydrate

The title compound, C₁₆H₁₁BrN₂O₂·H₂O, exists in a trans conformation with respect to the N=C bond [1.2815 (14) Å] and the benzofuran ring system forms a dihedral angle of 2.96 (5)° with the benzene ring. In the crystal, the ketone O atom accepts two O—H...O and one C—H...O hydrogen bond, and the water O atom accepts an N—H...O inter­action. Together, these lead to infinite layers lying parallel to (100).

N′-[(E)-3-Chloro-2-fluoro­benzyl­idene]-6-methyl­nicotinohydrazide monohydrate

The title compound, C₁₄H₁₁ClFN₃O·H₂O, exists in an E conformation with respect to the N=C bond. The pyridine ring forms a dihedral angle of 5.00 (9)° with the benzene ring. In the crystal, the ketone O atom accepts one O—H...O and one C—H...O hydrogen bond, the water O atom accepts one N—H...O and two C—H...O hydrogen bonds and the pyridine N atom accepts one O—H...N hydrogen bond, forming layers parallel to the ab plane.

(2E)-2-[(3-Methyl-5-phen­oxy-1-phenyl-1H-pyrazol-4-yl)methyl­idene]hydrazinecarbothio­amide

In the title compound, C₁₈H₁₇N₅OS, the mean plane of the pyrazole ring [maximum deviation = 0.0031 (12) Å] forms dihedral angles of 19.6 (4) and 9.3 (5)° with the two disorder components of the N-bound benzene ring (with equal occupancies for the two orientations) and a dihedral angle of 72.58 (8)° with the C—O-bonded benzene ring. The mol­ecule exists in a trans conformation with respect to the N=C bond [1.2792 (19) Å]. The mol­ecular structure features an intra­molecular C—H...O hydrogen bond, forming an S(6) ring. In the crystal, N—H...N and N—H...S hydrogen bonds result in the formation of zigzag layers lying parallel to (10-1).

3-Methyl-4-[2-(4-nitro­phen­yl)hydrazin-1-yl­idene]-5-oxo-4,5-dihydro-1H-pyrazole-1-carbothio­amide

The asymmetric unit of the title compound, C₁₁H₁₀N₆O₃S, contains two independent mol­ecules, each of which is stabilized by an intra­molecular N—H...O hydrogen bond, forming an S(6) ring motif. In one mol­ecule, the pyrazole ring forms a dihedral angle of 10.93 (14)° with the benzene ring. The corresponding dihedral angle in the other mol­ecule is 7.03 (14)°. In the crystal, mol­ecules are linked via pairs of (N,N)—H...O bifurcated acceptor bonds which, together with C—H...O hydrogen bonds, form sheets parallel to (001).

(E)-N′-(4-Chloro­benzyl­idene)-1-benzofuran-2-carbohydrazide monohydrate

The title compound, C₁₆H₁₁ClN₂O₂·H₂O, exists in an E conformation with respect to the N=C bond. The benzofuran ring system forms a dihedral angle of 1.26 (4)° with the benzene ring. In the crystal, mol­ecules are linked via (N,C)—H...O bifurcated acceptor hydrogen bonds and (O,O,C)—H...O trifurcated acceptor hydrogen bonds, forming layers parallel to the bc plane.

N′-[1-(4-Chloro­phen­yl)ethyl­idene]-5-methyl-1-(4-nitro­phen­yl)-1H-1,2,3-triazole-4-carbohydrazide

In the title compound, C₁₈H₁₅ClN₆O₃, the 1,2,3-triazole ring forms dihedral angles of 15.64 (5) and 57.50 (5)° with the two benzene rings. The dihedral angle between the two benzene rings is 72.26 (5)°. In the crystal, mol­ecules are linked via C—H...O hydrogen bonds into chains propagating along the b axis. A short O...C contact of 2.9972 (13) Å is observed.

N′-[(E)-1-(4-Bromo­phen­yl)ethyl­idene]-2-(2-methyl-4-nitro-1H-imidazol-1-yl)acetohydrazide

In the title compound, C₁₄H₁₄BrN₅O₃, the mean plane of the imidazole ring (r.m.s deviation = 0.004 Å) forms a dihedral angle of 58.13 (7)° with the benzene ring. In the crystal, mol­ecules are linked via N—H...O, C—H...O and C—H...N hydrogen bonds into a three-dimensional network. A short Br...Br contact of 3.4932 (2) Å also occurs.

2,3-Dibromo-3-(4-chloro­phen­yl)-1-(4-nitro­thio­phen-2-yl)propan-1-one

The title compound, C₁₃H₈Br₂ClNO₃S, exhibits whole-mol­ecule disorder over two orientations in a 0.805 (6):0.195 (6) ratio. The dihedral angles between the thio­phene ring [maximum deviations = 0.017 (4) and 0.033 (9) Å for the major and minor components, respectively] and the chloro-substituted phenyl ring are 32.1 (5) (major component) and 26.3 (18)° (minor component). In the crystal, C—H...Cl and C—H...O hydrogen bonds link the mol­ecules into sheets lying parallel to the bc plane. Aromatic π–π stacking inter­actions [centroid–centroid distance = 3.550 (7) Å] are also observed.

(E)-N′-(4-Meth­oxy­benzyl­idene)-2-(2-methyl-4-nitro-1H-imidazol-1-yl)acetohydrazide

In the title compound, C₁₄H₁₅N₅O₄, the central –C=N—N—C(=O)—C– bridge is nearly planar [maximum deviation = 0.037 (1) Å] and forms dihedral angles of 7.37 (9) and 73.33 (5)°, respectively, with the benzene and imidazole rings. The dihedral angle between the benzene and imidazole rings is 66.08 (9)°. The meth­oxy and nitro groups are nearly coplanar with the benzene and imidazole rings, respectively, with a C—O—C—C torsion angle of 5.9 (2)° and an O—N—C—C angle of −0.2 (2)°. In the crystal, mol­ecules are linked by a pair of N—H...O hydrogen bonds with an R₂²(8) ring motif, forming an inversion dimer. The dimers are further inter­connected by C—H...O hydrogen bonds into a sheet parallel to the (111) plane. A C—H...π inter­action is also observed between the sheets.

(2E)-2-{[3-Methyl-5-(2-naphth­yloxy)-1-phenyl-1H-pyrazol-4-yl]methyl­idene}hydrazinecarbothio­amide monohydrate

In the title compound, C₂₂H₁₉N₅OS·H₂O, the naphthalene ring system and the benzene ring [dihedral angle = 85.19 (8)°] make dihedral angles of 87.02 (9) and 14.41 (10)°, respectively, with the pyrazole ring. The mean plane through the 2-methyl­enehydrazinecarbothio­amide group [C—N—N—C(=S)—N; maximum deviation = 0.022 (1) Å] is slightly twisted from the pyrazole ring [dihedral angle = 5.60 (11)°]. In the crystal, mol­ecules are linked by N—H...S, N—H...O, O—H...S, O—H...N and C—H...S hydrogen bonds into sheets parallel to the ab plane. π–π inter­actions are also observed [centroid-to-centroid distances = 3.7778 (12) and 3.7010 (12) Å].