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21 citations found for Hamid, S.
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In the title compound, C14H14N2O2, the dihedral angle between the two benzene rings is 9.67 (10)°. Two intramolecular O—H
N and N—H
N hydrogen bonds involving the hydroxy and amino groups generate S(6) and S(5) ring motifs, respectively. In the crystal structure, N—H
O hydrogen bonds link neighboring molecules. Molecules are also stacked in a head-to-tail fashion along the c axis through π–π interactions [centroid–centroid separation of 3.7357 (12) Å] and are further linked by weak intermolecular C—H
π interactions, giving a zigzag arrangement along the b axis.
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The title compound, C22H20N2O4·2CHCl3, a new Schiff base compound, lies across a crystallographic inversion centre. An intramolecular O—H
N hydrogen bond generates a six-membered ring, producing an S(6) ring motif. Intermolecular bifurcated C—H
O hydrogen bonds involving the two O atoms of the Schiff base ligand and the H atom of the chloroform solvent of crystallization, generate an R21(5) ring motif. The crystal structure is stabilized by intermolecular C—H
π and π–π interactions [centroid to centroid distance = 3.6158 (10) Å]. In the crystal structure, molecules are stacked down the c axis.
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In the title compound, C22H20N2O4, the central benzene ring forms dihedral angles of 33.58 (7) and 35.27 (7)° with the terminal benzene rings. The molecular conformation is stabilized by two intramolecular O—H
N hydrogen bonds. In the crystal structure, the molecules are linked by intermolecular C—H
O interactions to form sheets parallel to the bc plane. The sheets are then stacked along the a axis. In addition, the crystal structure is stabilized by weak C—H
π interactions.
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In the title compound, C15H14O3, the dihedral angle between the two benzene rings is 23.33 (6)°. Molecules are linked into a chain along the b axis by intermolecular C—H
O interactions.
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The title compound, C21H20N2O2, a Schiff base ligand, contains two independent molecules (A and B) in the asymmetric unit, with similar conformations. In molecule A, the central benzene ring forms dihedral angles of 30.79 (13) and 23.56 (13)°, respectively, with the amino and benzyl benzene rings, while in molecule B these angles are 32.30 (13) and 13.13 (12)°. The molecular structure is stabilized by intramolecular N—H
N and C—H
O hydrogen bonds. The crystal structure is stabilized by N—H
N hydrogen bonds and N—H
π and C—H
π interactions.
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In the title molecule, C21H18N2O2, all bond lengths and angles are normal. Weak intermolecular N—H
N hydrogen bonds link the molecules into chains along the c axis. The crystal packing is further stabilized by van der Waals forces.
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In the main molecule of the title compound, C22H20N2O4·1.13CH4O, the dihedral angles between the benzimidazole plane and the two benzene rings are 80.53 (10) and 82.76 (10)°. The solvent molecules are disordered between three positions, with refined occupancies of 0.506 (13), 0.373 (13) and 0.249 (5). The crystal structure is stabilized by intermolecular O—H
O, O—H
N and C—H
O hydrogen bonds. The crystal studied was a merohedral twin [BASF ratio of 0.917 (1)/0.083 (1)].
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The asymmetric unit of the title compound, C22H20N2O4·H2O, comprises a substituted benzimidazole molecule and a water molecule of crystallization. The dihedral angles between the benzimidazole ring system and the two outer benzene rings are 16.54 (4) and 86.13 (4)°. The dihedral angle between the two hydroxy-substituted benzene rings is 82.20 (5)°. In the crystal structure, intermolecular O—H
O hydrogen bonds, involving the hydroxy groups and water molecules, form R44(8) ring motifs, and link symmetry-related molecules into extended chains along the c axis. The crystal structure is further stabilized by weak intermolecular C—H
O hydrogen bonds, weak C—H
π and π–π stacking [centroid–centroid = 3.6495 (6)–3.7130 (6) Å] interactions. Intramolecular O—H
O and O—H
N interactions are also present.
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In the title molecule, C22H19Cl3O5S, the methoxy group is slightly twisted from the plane of the attached benzene ring by a torsion angle of 18.96 (14)°. In the crystal structure, molecules are linked by intermolecular C—H
O interactions and short Cl
O contacts of 3.0170 (8) Å.
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In the crystal structure of the title compound, C11H16N2O3, molecules are linked by one O—H
N and two N—H
O intermolecular hydrogen bonds into a three-dimensional network, which incorporates R22(14) and R22(16) graph-set motifs.
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The title compound, C28H33N2S2P, adopts the thione tautomeric form, as supported by the C—S distance [1.6744 (18) Å]. The Schiff base exhibits an E conformation about the C=N bond but a Z conformation about the C—N bond. The terminal chain is disordered over two sets of sites with an occupancy ratio of 0.732 (3):0.268 (3). In the crystal, pairs of N—N—H hydrogen bonds between the thione groups link neighbouring molecules into centrosymmetric dimers.
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The title molecule lies about an inversion centre at the mid-point of the N—N bond and features two intramolecular O—H
N and two C—H
O hydrogen bonds, each of which forms an S(6) ring motif. In the crystal, molecules are linked by C—H
O hydrogen bonds into infinite zigzag chains propagating along the c-axis direction. π–π stacking interactions between the pyrone rings stack the molecules along b.
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The title compound, C20H24N2O6, was obtained as an unexpected product by the reaction of hydrazinium dithiocarbazate with 2,3,4-trimethoxybenzaldehyde in refluxing ethanol. The molecule lies on a center of inversion. The crystal packing is stabilized by weak intermolecular C—H
O interactions.
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A method is described for the growth from aqueous solution of Li1 - xHxIO3 single crystals. Unit-cell parameter, low-frequency resistivity and the temperature dependence of the α - β transition for several x values were determined. With an increase in x there is an increase in a0 and a decrease in C0 compared with the lattice constants of LiIO3. The maximum increase in a0 is 0.082 Å and the maximum decrease of C0 is 0.219 Å.
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The low-frequency dielectric behaviour, the piezoelectric constant g33 and Raman and IR spectra of Li1 - xHxIO3 have been measured. The amount of hydrogen, x, in the formula Li1 - xHxIO3 varies from 0.0 to 0.35. The curves ε33 = ε33(f) and tan δ = tan δ(f) show anomalous behaviour with respect to frequency and composition. The piezoelectric constant (g33) tends to a maximum at the composition x ≃ 0.04. A model of the low-frequency relaxation spectra and the high value of ε is discussed.
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Three new potassium hydrogen polyiodate compounds [KHn(IO3)1 +n] have been grown from aqueous solution. Their cell parameters, d values and space groups are reported.
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There are two molecules in the asymmetric unit of the title compound, C18H18N2O3. In each one, the benzimidazole ring system is essentially planar, with maximum deviations of 0.027 (1) and 0.032 (1)Å, and makes dihedral angles of 38.64 (6) and 41.48 (6)°, respectively, with the attached benzene rings. An intramolecular C—H
O hydrogen bond is observed in each molecule. The two independent molecules are connected into a dimer by two intermolecular O—H
N hydrogen bonds. In the crystal, molecules form a two-dimensional layers parallel to (012) via weak intermolecular C—H
O hydrogen bonds. In addition, weak π-π stacking interactions are observed with centroid–centroid distances of 3.5244 (12) and 3.6189 (12) Å.
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The molecule [1-(pyrazin-2-yl)ethylidene]hydrazine consists of an imine linkage with an N—N bond length of 1.3540 (14) Å. This asymmetric compound is nearly planar and adopts an E configuration about the azomethine C=N double bond. In the solid state, there are two intermolecular N—H
N interactions that interconnect the molecules into a two-dimensional network.
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The asymmetric unit of title compound, C11H14N2O4, consists of two crystallographically independent molecules (A and B). In each, intramolecular N—H
O hydrogen bonds generate S(6) ring motifs. The mean plane of the nitro group forms dihedral angles of 4.5 (3) and 0.5 (3)° with the benzene ring in molecules A and B, respectively. In molecule A, there is disorder of the butylamino group which corresponds to an approximate 180° rotation about the N—C(H) bond, forming two sites with refined occupancies of 0.722 (6) and 0.278 (6). Molecule B is similarly disordered but in addition there is further rotational disorder about the C(H)—C(H2) bond giving a ratio of occupancies for three components of 0.42:0.35:0.23. In the crystal structure, intermolecular O—H
O hydrogen bonds link molecules into centrosymmetric dimers generating R22(8) ring motifs. The crystal structure is also stabilized by weak intermolecular C—H
O interactions.
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