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In the title mol­ecule, C16H14ClF6NO, the cyclo­propane ring forms a dihedral angle of 70.82 (18)° with the benzene ring. The torsion angles about the ethyl­ene and amide bonds are −2.2 (5) (Cl—C—C—C) and 0.8 (5)° (O—C—N—C). A supra­molecular chain propagated by glide symmetry along [001] and mediated by N—H⋯O hydrogen bonds is observed in the crystal packing.

The title compound, C9H8Br2N2O3, is planar (r.m.s. deviation = 0.030 Å) with the exception of the terminal methyl group which lies out of the plane [1.219 (3) Å]. The conformation about the C=N double bond [1.268 (3) Å] is E. An intra­molecular N—H⋯N hydrogen bond occurs. Linear supra­molecular chains along the b axis mediated by O—H⋯O hydrogen-bonding inter­actions feature in the crystal structure. These chains are also stabilized by weak C—H⋯N contacts.

The title compound, C15H13ClN2O2, adopts an E conformation with respect to the azomethine C=N bond. The aniline and phenol rings are almost coplanar, making a dihedral angle of 3.33 (2)°. In the crystal, the mol­ecules lie about inversion centers, forming dimers that are connected by inter­molecular O—H⋯N hydrogen bonds, resulting in six-membered rings with graph-set motif R 2 2(6). In addition, there is a strong inter­molecular O—H⋯N hydrogen-bonding inter­action, resulting in an S(6) ring motif. Weak π–π inter­actions between the benzene rings [centroid–centroid distance = 3.809 (1) Å] further stabilize the crystal structure.

In the title compound, C20H21NO5, the dihedral angle between the mean planes through the two rings is 47.1 (8)°. The enoate group assumes an extended conformation. The hy­droxy­ethanimine group is essentially coplanar with the benzene ring, the largest deviation from the mean plane being 0.061 (1) Å for the O atom. In the crystal, mol­ecules are linked into cyclic centrosymmetric dimers with an R 2 2(6) motif via pairs of O—H⋯N hydrogen bonds. Inter­molecular C—H⋯O hydrogen bonds form a C(8) chain along the b axis. The crystal packing is further stabilized by C—H⋯π inter­actions.

In the title compound, C14H11BrN2O2, the mean planes of the two benzene rings are almost parallel to each other, making a dihedral angle of 4.09 (1)°. An intra­molecular O—H⋯N hydrogen bond occurs. In the crystal, inter­molecular O—H⋯N and C—H⋯O hydrogen bonds link the mol­ecules into a chain-like supra­molecular structure.

Mol­ecules of the title compound, C23H30N2O4, are located on a crystallographic mirror plane. The mol­ecule has a curved shape with the dihedral angle formed between the two benzene rings being 55.26 (5)°. Intra­molecular O—H⋯N hydrogen bonds are noted. In the crystal, supra­molecular layers are formed in the ac plane owing to the presence of C—H⋯π inter­actions.

In the title compound, [Co(C16H16NO2)3], the CoIII atom is six-coordinated in an irregular octa­hedral geometry by three N,O-chelating 2-{[2-(4-meth­oxy­phen­yl)eth­yl]imino­meth­yl}phenolate groups. One of the three meth­oxy group is disordered over two sets of sites with an occupancy ratio of 0.768 (5):0.232 (5). The crystal packing can be described by alternating zigzag layers of organic ligands and CoN3O3 octa­hedra along the c axis. There are no classical hydrogen bonds in the structure, but C—H⋯π inter­actions occur.

In the title compound, C15H13BrN2O2, he oxime unit adopts an E conformation with respect to the O—H group. A classical intra­molecular O—H⋯N hydrogen bond results in the formation of a six-membered ring. The crystal structure is stabilized by inter­molecular O—H⋯N hydrogen bonds between the hydr­oxy groups and the oxime N atoms. In addition, the crystal structure also features short inter­molecular Br⋯Br short contacts with a distance of 3.8768 (5) Å.

In the title thio­semicarbazone derivative, C9H10N4OS·H2O, intra­molecular N—H⋯N hydrogen bonds result in the formation of two nearly coplanar five- and six-membered rings, which are also almost coplanar with the adjacent phenyl ring. The oxime group has an E configuration and is involved in inter­molecular O—H⋯O hydrogen bonding as a donor. In the crystal structure, intra­molecular O—H⋯S and N—H⋯N and inter­molecular O—H⋯O and N—H⋯S hydrogen bonds generate edge-fused R 2 2(8) and R 4 1(11) ring motifs. The hydrogen-bonded motifs are linked to each other to form a three-dimensional supra­molecular network.

In the title compound, C20H21NO4, the two benzene rings are almost perpendicular to each other, making a dihedral angle of 86.1 (7)°. The hy­droxy­ethanimine group is essentially coplanar with the benzene ring, the largest deviation from the mean plane of the hy­droxy­ethanimine [C=N—OH] group being 0.011 (1) Å for the O atom. An intra­molecular C—H⋯O hydrogen bond occurs. The mol­ecules are linked into cyclic centrosymmetric R 2 2(6) dimers via O—H⋯N hydrogen bonds. Inter­molecular C—H⋯O hydrogen bonds link the mol­ecules, forming a C(8) chain along the a axis. The crystal packing is further stabilized by C—H⋯π inter­actions.

In the title compound, C15H17BrN2O3, the dihedral angle between the benzene and pyrazole rings is 5.63 (2)°. The crystal packing is stabilized by weak π–π stacking inter­actions [centroid–centroid distance = 3.927 (5) Å] and inter­molecular C—H⋯O and C—H⋯Br hydrogen bonds.

The mol­ecule of the title compound, C5H9NO3, is essentially planar [the maximum deviation for a non-H atom from the mean plane is 0.021 (3) Å] due to the π-conjugation of the hydroxy­imino and carbonyl groups, which are trans to each other; ab initio calculations in vacuo at the DFT (B3LYP/6–311G**++) level of theory confirmed that E conformer is indeed the lowest in energy. The packing in crystal structure is influenced by strong inter­molecular O—H⋯N hydrogen-bonding inter­actions between oxime groups and also by π-stacking of the mol­ecules due to the carbonyl and oxime group orbital overlap [inter­planar distance between adjacent mol­ecules = 3.143 (4) Å]. Jointly, these factors afford infinite 6.32 Å thick mol­ecular sheets, where the plane of each mol­ecule is perpendicular to the plane of the sheet. Seen from above, the mol­ecules within the sheet are arranged in a herringbone pattern. Such sheets form a stack due to weak van der Waals inter­actions; the gap between adjacent sheets is 2.07 Å.

In the title compound, C19H19NO4, the dihedral angle between the mean planes through the benzene rings is 82.18 (7)°. The C=N double bond is trans-configured. The mol­ecules are linked into centrosymmetric dimers via pairs of O—H⋯N hydrogen bonds with the motif R 2 2(6). The crystal packing also features C—H⋯O inter­actions. The methyl group attached to one of the aromatic rings is disordered over two almost equally occupied positions [occpancy ratio = 0.51 (4):0.49 (4)].

In the title compound, C17H18O5, the pyrogallol group is almost coplanar with the mean plane of the attached carbonyl group [dihedral angle of 1.95 (13)°] and makes a dihedral angle of 56.01 (10)° with the other benzene ring. Of the three meth­oxy groups, only one is significantly twisted relative to its attached benzene ring [C—O—C—C torsion angles of 4.0 (5), 3.9 (6) and −106.3 (4)°]. Intra­molecular O—H⋯O and C—H⋯O hydrogen bonds help to establish the conformation, and the packing is consolidated by C—H⋯O inter­actions and π–π stacking interactions [centroid–centroid separation = 3.735 (2) Å].

In the crystal structure of the title compound, C20H26O7, a lignin model compound, the asymmetric unit contains two mol­ecules which adopt almost identical overall conformations with some deviation in the region of the terminal hydroxyl groups. The two mol­ecules are linked by an inter­molecular O—H⋯O hydrogen bond. They also develop intra­molecular O—H⋯O hydrogen bonds.

In the title compound, [Fe(C9H13N4O4)(NH3)2], the FeIII atom, lying on a mirror plane, is coordinated by four N atoms of a triply deprotonated tetra­dentate N-[2-(hy­droxy­imino)­propion­yl]-N′-[2-(oxidoimino)­propion­yl]propane-1,3-diaminide ligand in the equatorial plane and two N atoms of two ammonia mol­ecules at the axial positions in a distorted octa­hedral geometry. A short intra­molecular O—H⋯O hydrogen bond between the cis-disposed oxime O atoms stabilizes the pseudo-macrocyclic configuration of the ligand. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds into a three-dimensional network. The ligand has a mirror-plane symmetry. One of the methyl­ene groups of the propane bridge is disordered over two sets of sites with equal occupancy factors.

In the title compound, C9H10N4O2, the pyridine ring is twisted by 16.5 (1)° from the mean plane defined by the remaining non-H atoms. An intra­molecular N—H⋯N inter­action is present. In the crystal, inter­molecular O—H⋯N and N—H⋯O hydrogen bonds link mol­ecules into layers parallel to the bc plane. The crystal packing exhibits π–π inter­actions indicated by the short distance of 3.649 (1) Å between the centroids of the pyridine rings of neighbouring mol­ecules.

The Ni atom of the title complex, [Ni(C8H8NO3)2]·2C3H7NO, lies on a center of inversion in a square-planar N2O2 coordination environment. An intra­molecular O—H⋯O hydrogen bond exists between the oximic hydr­oxy group of one ligand and the metal-coordinated O atom of the symmetry-related ligand. The dimethyl­formamide solvent mol­ecules are connected to the phenolate groups of the complex via O—H⋯O hydrogen bonds.

The mol­ecule of the title compound, C10H11N3O3, adopts an all-trans conformation and is approxomately planar, the largest deviation from the least-squares plane through all non-H atoms being 0.261 (1) Å. An intra­molecular O—H⋯N hydrogen bond occurs. In the crystal, the mol­ecules are packed into layers lying parallel to the ab plane by π-stacking inter­actions between the benzene ring of one molecule and the C—N bond of the oxime group of another molecule; the shortest inter­molecular C⋯C separation within the layer is 3.412 (1) Å. The layers are connected by O—H⋯O and N—H⋯O hydrogen bonds.

The title compound, C22H18N2O3 is the second monoclinic polymorph (P21/c) of the compound, the first being reported in space group P21 [Bertolasi et al. (1993 ▶). J. Chem. Soc. Perkin Trans. 2, pp. 2223–2228]. In the mol­ecular structure of the title compound, the inter­planar angle between the benzoyl units is 80.04 (5)°, while the corresponding angles between the phenyl­hydrazinyl­idene and benzoyl groups are 36.11 (5) and 55.77 (2)°. A strong resonance-assisted intra­molecular N—H⋯O hydrogen bond is found. In the crystal, the entire supra­molecular structure is constructed by weak inter­molecular C—H⋯O inter­actions and an inter-ring π–π inter­action [centroid–centroid distance = 3.6088 (8) Å].

In the title compound, C26H24N4O2, the dihedral angles between the central pyrazole ring and the other three benzene rings are 40.02 (3), 77.51 (5) and 55.72 (3)°. A strong intra­molecular N—H⋯O hydrogen bond forms a six-membered ring with an S(6) motif. In the crystal structure, a weak inter­molecular C—H⋯N inter­action with graph-set motif R 2 2(8) and C—H⋯O hydrogen bonds link each mol­ecule to three others, forming an infinite two-dimensional supra­molecular structure.

The title compound, C18H16O7·H2O, is a flavonoid isolated from Dodonaea viscosa­. The benzopyran ring system of the flavonoid is essentially planar [maximum deviation = 0.025 (2) Å] and inclined at 5.83 (2)° to the attached benzene ring. The water of hydration is involved in extensive hydrogen bonding, assembling the mol­ecules into a supra­molecular network via classical inter­molecular O—H⋯O hydrogen bonding. The crystal structure is further stabilized by π–π stacking inter­actions [centroid–centroid distance between benzene rings = 3.564 (3) Å].

The title anilide–imine compound, C24H26N2O, features an intra­molecular N—H⋯N hydrogen bond involving the imine and anilide groups to generate an S(6) ring motif. The mol­ecule displays an E configuration about the imine C=N double bond, with the dihedral angle between the two benzene rings being 86.5°. The packing is stabilized by three different C—H⋯π inter­actions.

The hydrazone mol­ecule in title monohydrate, C14H13N3O4·H2O, is almost coplanar, the dihedral angle between the terminal benzene rings being 3.22 (15)°; the nitro group is coplanar with the benzene ring to which it is bonded [O—N—C—C = −2.8 (4)°]. The hy­droxy group forms an intra­molecular hydrogen bond with the imine N atom, and the conformation about the imine bond [1.305 (3) Å] is E. In the crystal, supra­molecular layers in the (203) plane are connected into a double layer via water–nitro O—H⋯O hydrogen bonds, along with π–π inter­actions [ring centroid–centroid distance = 3.7859 (19) Å].

In the title compound, C18H16ClNO4, the dihedral angle between the mean planes through the aromatic rings is 83.8 (8)°. The hy­droxy­ethanimine group is essentially coplanar with the ring to which it is attached [O—N—C—C torsion angle = −177.96 (13)°]. The mol­ecules are linked into centrosymmetric R 2 2(6) dimers via O—H⋯N hydrogen bonds. The crystal packing is further stabilized by C—H⋯O inter­actions.