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, [ZnCl2(C10H12N4O2)]·0.5H2O, was readily prepared by the reaction between ZnCl2 and 2-hydroxyimino-N′-[1-(2-pyridyl)ethylidene]propanohydrazide. The Zn atom has a distorted trigonal–bipyramidal geometry with two Cl atoms and one azomethine N atom in the equatorial plane and one pyridine N atom and one amide O atom in the axial positions. In the crystal structure, complex molecules are connected in pairs by N—H⋯Cl hydrogen bonds, formed between the amide NH of one molecule and the Cl atom of a neighboring one. Molecular pairs are connected by hydrogen bonds involving the uncoordinated water molecule, which lies on a twofold axis.
The title compound, C13H16N2O3, adopts an E configuration with respect to the C=N bond and an intramolecular N—H⋯N hydrogen bond results in the formation of a six-membered ring. In the crystal, intermolecular O—H⋯O hydrogen bonds link the molecules into a chain propagating along the b axis. Very weak π–π stacking interactions [centroid–centroid distance = 4.18 (2) Å] may further consolidate the packing, forming a two-dimensional supramolecular network.
In the title compound, C15H13N3O3, the dihedral angle formed by the two benzene rings is 44.23 (2)°. The crystal structure is stabilized by aromatic π–π stacking interactions, with centroid-centroid distances of 3.825 (3) and 3.870 (4) Å between the aniline and the nitrobenzene rings of neighbouring molecules, respectively. In addition, the stacked molecules exhibit intermolecular C—H⋯N and C—H⋯O interactions.
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.
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(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(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.
The title compound, C8H7ClN2O2, is an intermediate in the synthesis of 5-chloroisatin, which can be further transformed to 5-chloro-2-indolinone via a Wolff–Kishne reduction. The C2N acetamide plane forms a dihedral angle of 6.3 (3)° with the benzene ring. An intramolecular C—H⋯O interaction results in the formation of a six-membered ring. In the crystal, intermolecular N—H⋯O, N—H⋯N and O—H⋯O hydrogen bonds link the molecules into multimers, forming sheets.
The title compound, C10H12N4O2, features an intramolecular N—H⋯N hydrogen bond formed between the imine NH and oxime N atoms. The oxime group and the amide C=O bond are anti to each other. In the crystal, molecules are connected by O—H⋯O hydrogen bonds into supramolecular zigzag chains along the c axis.
The title hydrazide compound, C20H24N2O2, exists in a trans configuration with respect to the acyclic C=N bond and an intramolecular O—H⋯N hydrogen bond generates an S(6) ring motif. The mean plane through the formohydrazide unit is essentially planar [maximum deviation = 0.025 (2) Å], and forms dihedral angles of 24.45 (16) and 87.14 (16)° with the two benzene rings. In the crystal structure, intermolecular N—H⋯O and C—H⋯O hydrogen bonds link neighbouring molecules into extended chains along the c axis, which incorporate R
2(16) ring motifs. An intermolecular C—H⋯π interaction is also observed.
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(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, 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(6) dimers via O—H⋯N hydrogen bonds. The crystal packing is further stabilized by C—H⋯O interactions.
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(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, 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.
There are three independent 3-hydroxyimino-1-methylindolin-2-one molecules and a water molecule in the asymmetric unit of the title compound, 3C9H8N2O2·H2O. The crystal packing is stablized by O—H⋯O and O—H⋯Nhydrogen bonds between 3-hydroxyimino-1-methylindolin-2-one molecules and the water molecule and weak π–π stacking interactions [centroid–centroid distances in the range 3.446 (2)–3.983 (2) Å], forming a two-dimensional network.
The cation of the salt, [Mn2(C14H14N4)3(H2O)2](ClO4)4, lies on a center of inversion, the center lying midway along the ethylene chain of the bridging N,N′-bis(2-pyridylmethylene)ethane-1,2-diamine ligand. The Mn atom is chelated by two atoms N atoms of this bridging ligand, and is also coordinated by four N atoms of another ligand. The Mn atom is seven-coordinated in a pentagonal-bipyramidal environment. The crystal structure displays intermolecular π–π interactions between adjacent pyridine rings, with a shortest centroid–centroid distance of 3.784 (3) Å. The perchlorate is linked to the dinuclear cation by O—H⋯O hydrogen bonds.
The asymmetric unit of the title compound, C13H8ClI2NO, contains half of the molecule situated on a mirror plane. The hydroxy group is involved in the formation of an intramolecular O—H⋯N hydrogen bond. π–π interactions between the benzene rings of neighbouring molecules [centroid–centroid distance = 3.629 (3) Å] form stacks along the b axis. In the crystal, weak C—H⋯O and C—H⋯Cl interactions are observed.
In the title compound, C18H17NO4, the hydroxyethanimine group is essentially coplanar with the ring to which it is attached [C—C—N—O torsion angle = 179.94 (14)°]. The molecules are linked into cyclic centrosymmetric R
2(6) dimers via O—H⋯N hydrogen bonds and the crystal packing is further stabilized by C—H⋯O interactions.
In the title compound, C16H16N2O3·H2O, the benzene rings are nearly coplanar with each other, forming a dihedral angle of 4.46 (3)°. There is a strong intramolecular O—H⋯N hydrogen bond which results in a six-membered ring. In the crystal, the molecules are connected into a three-dimensional network via O—H⋯O and O—H⋯N intermolecular hydrogen bonds, forming a centrosymmetric ring along the b axis with graph-set motif R
4(10). In addition, the short distances between the centroids of six-membered rings [3.555 (1) Å], indicate the existence of π–π stacking interactions, which may stabilize the crystal structure.
In the title compound, C14H16N6O2, the dihedral angles formed by the mean plane of the acetohydrazide group [maximum deviation 0.0629 (12) Å] with the pyrazole and pyridine rings are 81.62 (6) and 38.38 (4)° respectively. In the crystal, molecules are connected by N—H⋯O and O—H⋯N hydrogen bonds into supramolecular chains extending parallel to the c-axis direction.
The asymmetric unit of the triclinic polymorph of the title compound, C21H25N3O3, consists of two molecules, whereas for the monoclinic polymorph Z′ = 1 [Fun et al. (2009 ▶). Acta Cryst. E65, o445]. The two molecules exhibit an E configuration with respect to the C=N bond. The molecules are linked into dimers by N—H⋯O and C—H⋯O hydrogen bonds forming R
2(8) ring motifs. In addition, π–π interactions occur between nitrophenyl groups [minimum centroid–centroid distance 3.940 (2) Å], stacking the molecules along the ac plane.
The molecule of the title compound, C21H25N3O3, exists in a trans configuration with respect to the ethylidene unit. The dihedral angle between the two substituted benzene rings is 86.99 (7)°. The nitro group is twisted from the attached benzene ring at an angle of 17.02 (7)°. In the crystal structure, molecules are linked by pairs of N—H⋯O hydrogen bonds in a face-to-face manner into centrosymmetric dimers. These dimer units are further linked into chains along the c axis by weak C—H⋯O interactions. These chains are stacked along the b axis. The crystal is further stabilized by weak C—H⋯π interactions.
In the title compound, C17H11ClN2O3, an intramolecular O—H⋯N hydrogen bond influences the molecular conformation; the naphthol system and the substituted benzene ring form a dihedral angle of 3.5 (1)°. In the crystal, weak intermolecular C—H⋯O hydrogen bonds link molecules into chains in the  direction The crystal packing exhibits π–π interactions between the aromatic rings from the neighbouring molecules, with a centroid–centroid distance of 3.566 (7) Å.
In the title compound, C9H10N4O2·H2O, the oxime unit has an E configuration, and an intramolecular N—H⋯N hydrogen bond results in the formation of a planar five-membered ring, which is oriented with respect to the aromatic ring at a dihedral angle of 74.82 (17)°. In the crystal structure, intermolecular O—H⋯O and N—H⋯O hydrogen bonds link the molecules and R
2(8) ring motifs are apparent.
The title molecule, C11H10N2O6, has a Z conformation about the C=N bond of the oxime unit. There are significant twists from planarity throughout the molecule, the most significant being between the hydroxyimino and ester groups which are effectively orthogonal with an N—C—C—Ocarbonyl torsion angle of 91.4 (2)°. The crystal packing features oxime–benzoyl O—H⋯O contacts that lead to chains along  and C—H⋯O interactions also occur.