4-(4-Bromo­phen­yl)-7,7-dimethyl-2-methyl­amino-3-nitro-7,8-di­hydro-4H-chromen-5(6H)-one including an unknown solvate

In the title compound, C₁₈H₁₉BrN₂O₄, the chromene unit is not quite planar (r.m.s. deviation = 0.199 Å), with the methyl C atoms lying 0.027 (4) and 1.929 (4) Å from the mean plane of the chromene unit. The six-membered carbocyclic ring of the chromene moiety adopts an envelope conformation, with the dimethyl-substituted C atom as the flap. The methyl­amine and nitro groups are slightly twisted from the chromene moiety, with C—N—C—O and O—N—C—C torsion angles of 2.7 (4) and −0.4 (4)°, respectively. The dihedral angle between the mean plane of the chromene unit and the benzene ring is 85.61 (13)°. An intra­molecular N—H...O hydrogen bond generates an S(6) ring motif, which stabilizes the mol­ecular conformation. In the crystal, mol­ecules are linked via N—H...O hydrogen bonds, forming hexa­gonal rings lying parallel to the ab plane. A region of disordered electron density, most probably disordered ethanol solvent mol­ecules, occupying voids of ca 432 ų for an electron count of 158, was treated using the SQUEEZE routine in PLATON [Spek (2009). Acta Cryst. D65, 148–155]. Their formula mass and unit-cell characteristics were not taken into account during refinement.

(E)-N′-(3,4-Di­meth­oxy­benzyl­idene)nicotinohydrazide monohydrate

In the title hydrated compound, C₁₅H₁₅N₃O₃·H₂O, the nicotinohydrazide mol­ecule adopts a trans conformation with respect to the C=N double bond. The dihedral angle between the benzene and pyridine rings is 5.10 (14)°. In the crystal, the solvent water mol­ecule acts as an acceptor, forming an N—H...O hydrogen bond supported by two C—H...O contacts. It also acts as a donor, forming bifurcated O—H...(O,O) and O—H...N hydrogen bonds that combine with the former contacts to form zigzag chains of mol­ecules along the c-axis direction. An additional O—H...O donor contact completes a set of six hydrogen bonds to and from the water mol­ecule and connects it to a third nicotinohydrazide mol­ecule. This latter contact combines with weaker C—H...O hydrogen bonds supported by a C—H...π contact to stack mol­ecules along b in a three-dimensional network.

(E)-1-([1,1′-Biphen­yl]-4-yl)-3-(2-methyl­phen­yl)prop-2-en-1-one

In the title mol­ecule, C₂₂H₁₈O, the o-tolyl ring is connected through a conjugated double bond. The mol­ecule adopts an E conformation and the C—C=C—C torsion angle is 178.77 (13)°. The overall conformation may be described by the values of dihedral angles between the different planes. The terminal rings are twisted by an angle of 54.75 (8)°, while the biphenyl part is not planar, the dihedral angle between the planes of the rings being 40.65 (8)°. The dihedral angle between the benzene rings is 14.10 (7)°. There are three weak C—H...π inter­actions found in the crystal structure. No classic hydrogen bonds are observed.

3-Methyl­benzo[1,2-c:5,4-c′]dichromen-6(8H)-one

The title compound, C₂₁H₁₄O₃, crystallizes with eight independent mol­ecules (A–H) in the asymmetric unit which are arranged in four groups of two mol­ecules each (AB, CD, EF and GH). In each mol­ecule, the pyran-2-one ring is planar (r.m.s. deviations vary from 0.001 to 0.017 Å), while the pyran ring has a screw-boat conformation. In the crystal, mol­ecules stack in two columns, along the [10-1] direction, composed of mol­ecules C, B, E and G, and D, A, F and H. Mol­ecules A and F are linked via C—H...O hydrogen bonds. In addition, there are a number of C—H...π contacts present involving all of the mol­ecules. These inter­actions result in the formation of a three-dimensional network.

4-Fluoro-N-(4-hy­droxy­benzyl­idene)aniline

In the title compound, C₁₃H₁₀FNO, the benzene ring planes are inclined at an angle of 50.52 (8)°. A characteristic of aromatic Schiff bases with N-aryl substituents is that the terminal phenyl rings are twisted relative to the plane of the HC=N link between them. In this case, the HC=N unit makes dihedral angles of 10.6 (2) and 40.5 (2)° with the hy­droxy­benzene and fluro­benzene rings, respectively. In the crystal, O—H...N and C—H...F hydrogen bonds lead to the formation of chains along the c- and b-axis directions, respectively. C—H...π contacts link mol­ecules along a and these contacts combine to generate a three-dimensional network with mol­ecules stacked along the b-axis direction.

Crystal structure of 3-({[(thio­phen-2-yl)methyl­idene]hydrazin­yl}carbon­yl)pyridinium chloride dihydrate

In the title compound, C₁₁H₁₀N₃OS⁺·Cl⁻·2H₂O, the organic cation exhibits a dihedral angle of 21.26 (8)° between the mean planes of the pyridine and thio­phene rings, and dihedral angles of 15.11 (9) and 6.49 (9)° between the mean planes of the hydrazide moiety and the pyridine and thio­phene rings, respectively. In the crystal, the organic cation, the chloride counter-anion and the two water mol­ecules of crystallization are linked through an intricate hydrogen-bonding network consisting of O—H...O, O—H...N, N—H...Cl, C—H...Cl, C—H...O, N—H...O, O—H...Cl and C—H...S inter­actions that consolidate a three-dimensional network.

Crystal structure of (Z)-3-{3-(4-chloro­phen­yl)-2-[(4-chloro­phen­yl)imino]-2,3-di­hydro­thia­zol-4-yl}-2H-chromen-2-one

In the title compound, C₂₄H₁₄Cl₂N₂O₂S, the 2H-chromene ring system is approximately planar, with a maximum deviation of 0.025 (2) Å. The thia­zole ring is almost planar, with an r.m.s. deviation of 0.0022 Å, and makes a dihedral angle of 58.52 (7)° with the chromene ring system. The chromene ring system is inclined at angles of 58.3 (1) and 55.39 (9)° with respect to the two chloro­phenyl rings. The two chloro­phenyl rings show significant deviation from coplanarity, with a dihedral angle between them of 47.69 (8)°. The crystal structure features C—H...Cl inter­actions extending in (100) and propagating along the a-axis direction and weak π–π inter­actions [centroid–centroid separation = 3.867 (2) Å].