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In the title benzylideneaniline Schiff base, C18H22N2O, the aromatic rings are inclined to each other by 46.01 (6)°, while the Car—N= C—Car torsion angle is 176.9 (1)°. In the crystal, the only identifiable directional interaction is a weak C—H...π hydrogen bond, which generates inversion dimers that stack along the a-axis direction.

The title Schiff base compounds, C22H26N4O (I) and C18H16FN3O (II), were each synthesized by a single-step condensation reaction. The substituted benzylidene ring is inclined to the pyrazole ring mean planes by 22.92 (7)° in I and 12.70 (9)° in II. The phenyl ring of the 4-aminoantipyrine unit is inclined to the pyrazole ring mean plane by 54.87 (7)° in I and by 60.44 (8)° in II. In the crystal of I, the molecules are linked by C—H...O hydrogen bonds and C—H...π interactions to form layers lying parallel to (001). In the crystal of II, the molecules are linked by C—H...O and C—H...F hydrogen bonds and C—H...π interactions, thereby forming layers lying parallel to (010). Hirshfeld surface analysis was employed to further quantify the interatomic interactions in the crystals of both compounds.

The crystal structure of the title compound, C13H9Br2N [systematic name: (E)-N,1-bis(4-bromophenyl)methanimine], is a second polymorph (Form II) crystallizing in the orthorhombic space group Pccn. The first polymorph (Form I) crystallizes in the monoclinic space group P21/c [Bernstein & Izak (1975). J. Cryst. Mol. Struct. 5, 257–266; Marin et al. (2013). J. Mol. Struct. 1049, 377–385]. The molecule is disordered about an inversion center situated in the middle of the C=N bond, similar to the situation in the monoclinic polymorph: the C=N bond length is 1.243 (7) Å. In the crystal, molecules stack along the b-axis direction and are linked by C—H...π interactions. The interatomic contacts in the crystal for both polymorphs were studied by Hirshfeld surface analysis and have notable differences. The solid-state fluorescence spectrum of Form II shows an emission peak at ca 469 nm. The two-photon absorption coefficient measured from the open aperture Z-scan technique is 1.3 × 10 −11 m W−1, hence, Form II shows optical limiting behaviour.

A nonlinear optical single crystal of bis (cytosinium) tartarate monohydrate (BCTM) was grown by slow evaporation method at room temperature. Single crystal X-ray diffraction study revealed their cell parameters and corresponding space group. Different functional groups were identified by using FTIR spectral analysis. Phase purity of the grown crystal was analysed by chemical etching and powder X-ray diffraction studies. The mechanical strength of the grown crystal was estimated using Vickers microhardness test. The thermal stability of the grown crystal was investigated by TGA-DTA studies. The optical absorption study was carried out in the wavelength range of 190–1100 nm. The dielectric response of the grown crystal was studied as a function of frequency at different temperatures. Second harmonic generation efficiency (SHG) was measured by Kurtz and Perry powder technique. The Z-scan pattern clearly evidenced that the BCTM exhibits sequential two photon absorption induced reverse saturable absorption.

Metal oxide frame works along with carbon materials have been attracting tremendous attention of researches as the potential materials for energy and environmental remediation. In the present work heterostructures of (ZnO/CuO)/rGO ternary nanocomposites were synthesized by solid-state method. The crystalline structure of the nanoparticles was obtained from the XRD analysis. Optical band gap of the ZnO nanoparticles (3.1 eV) is tuned to 2.8 eV in the synthesized (ZnO/CuO)/rGO ternary nanocomposites. Field emission scanning electron microscope images of the (ZnO/CuO)/rGO ternary nanocomposites revealed formation of well-developed flowers like morphology of (ZnO/CuO) nanoparticles on rGO sheets. Photoluminescence spectroscopy analysis of (ZnO/CuO)/rGO ternary nanocomposites show enhancement in the electron-hole pair separation and thereby diminishing electron-hole pairs recombination rates effectively. In the present work, the photocatalytic activity of the ZC3G15 ternary nanocomposites show 99% and 93% of degradation efficiency respectively against RhB dye and 4-chlorophenol for 20 min under visible light irradiation. Thus, the simple solid-state method provides the effective ternary nanocomposites heterostructures light harvesting material for energy and environmental remediation. Keywords: Powders: solid state reaction, Nanocomposites, X-ray methods, Optical properties, Reduced graphene oxide, Photocatalytic activity

The present work reports on a novel ternary nanocomposite of ZnO rods encapsulated by graphitic like carbon nitride (g-C3N4) and coupled with graphene oxide (GO) prepared by ultrasonication assisted hydrothermal method which provides enhanced photocatalytic activity and stability. Field emission scanning electron microscopy analysis showed that the surface morphology of ZnO, g-C3N4 (prepared by heating method) and the GO contains nanorods structures, sheet like structures and sheets with porous structures respectively. Formation of rod like structures of ZnO and thin sheet like structures of g-C3N4 were observed from transmission electron microscopy analysis. Transmission electron microscopy analysis of g-C3N4 (6 wt%)/ZnO nanocomposites showed that ZnO nanorods are encapsulated by the thin sheets of g-C3N4 and g-C3N4(6 wt%)/ZnO/GO (30 mg) ternary nanocomposites contains porous structures of GO. The optical band gap of ZnO nanoparticles was shifted from 3.08 eV to 2.85 eV for g-C3N4(6 wt%)/ZnO/GO(30 mg) ternary nanocomposites. Under visible light irradiation the ZnO nanorods and g-C3N4 (6 wt%)/ZnO showed photodegradation efficiency of ∼21% and 90% respectively for 120 min whereas g-C3N4 (6 wt%)/ZnO/GO(30 mg) showed about 99% photodegradation efficiency in a time period of 14 min. The recycle process carried out for g-C3N4(6 wt%)/ZnO/GO(30 mg) composites up to five cycles showed 91.5% of photodegradation in the fifth cycle for a time period of 14 min. Total Organic Carbon (TOC) analysis shows removal of carbon content 83% in 28 min. The Gas Chromatography-Mass Spectroscopy analysis shows the intermediate products of 1,2 benzenedicarboxylic acid and phthalic acid during the RhB dye photodegradation process. The radical trapping experiment reveals that the photo-induced holes (h+) are one of the main reactive species involved in the degradation of the RhB. Keywords: g-C3N4/ZnO/GO ternary nanocomposite, Ultrasonication, Hydrothermal, Optical band gap, Raman analysis, Photocatalysts

Well-developed transparent single crystals of bis-glycine lithium bromide were grown by the slow evaporation method. The grown crystals were characterized by powder X-ray diffraction analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis and differential scanning calorimetry analyses. UV–VIS–NIR spectrum shows excellent transmission in the UV, visible and NIR regions. Mechanical properties of the grown crystals were studied using the Vickers microhardness tester. Third-order nonlinear optical properties were studied in detail by the Z-scan technique with He–Ne laser radiation of wavelength 632.8 nm and the corresponding nonlinear refractive index, absorption coefficient and optical susceptibility were calculated.

Nonlinear optical material, 4-chloro-4′methoxy benzylideneaniline (CMOBA) was synthesized and single crystal of CMOBA was grown by slow evaporation method. Functional groups of CMOBA were identified using the Fourier transform infrared spectral analysis and the molecular structure was confirmed by 1H and 13C NMR spectral analyses. Grown crystal was subjected to single crystal X-ray diffraction analysis to obtain unit cell parameters. UV–Vis-NIR optical study revealed that the UV cut off occurs at the wavelength of about 390 nm and the crystal is transparent in the wavelength range of 400–1100 nm. Second harmonic generation efficiency of the powdered CMOBA is about 3.7 times that of potassium dihydrogen orthophosphate. By using open aperture Z-scan (Nd:YAG, 532 nm, 5 ns) the measured effective two-photon absorption coefficient β was 3 × 10−12 m/W. The melting point of the material is ∼125 °C. The dielectric constant and dielectric loss were estimated for various frequencies at different temperatures.

The asymmetric unit of the title cystosinium salt derivative, 2C4H6N3O+·C4H4O62−·H2O, contains two cytosinium cations, one tartaric acid anion and a water molecule. The two cytosinium cations are almost planar (r.m.s. deviations of the fitted atoms are 0.0151 and 0.0213 Å). The crystal structure features C—H...O, N—H...O and O—H...O interactions. Further C—O...π and π–π interactions are observed along the ab plane, contributing to the crystal stability.

In the title coordination polymer, {[CdBr2(C5H9NO2)]·H2O}n, the CdII ion is coordinated by four bromido ligands and two carboxylate oxygen atoms of two symmetry-related proline ligands, which exist in a zwitterionic form, in a distorted octahedral geometry. There is an intramolecular N—H...O hydrogen bond between the amino group and the carboxylate fragment. Each coordinating ligand bridges two CdII atoms, thus forming polymeric chains running along the c-axis direction. The water molecules of crystallization serve as donors for the weak intermolecular O—H...O and O—H...Br hydrogen bonds that link adjacent polymeric chains, thus forming a three-dimensional structure. N—H...O and N—H...Br hydrogen bonds also occur.

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.

In the title compound, C15H21ClN2OS, the central chromophore moiety (C2N2OS) is approximately planar, with a maximum deviation of −0.027 (1) Å, and is oriented at a dihedral angle of 86.7 (1)° with respect to the chlorophenyl ring. An intramolecular N—H...O hydrogen bond stabilizes the molecular conformation. In the crystal, molecules associate via N—H...S hydrogen bonds, forming inversion dimers with motif R22(8). These dimers are further connected by N—H...O hydrogen bonds, forming R22(12) dimers. As a result, hydrogen-bonded chains running along [110] are formed. C—H...S interactions also occur. The terminal two C atoms of the butyl chain are disordered over two positions with an occupancy ratio of 0.54:0.46.

In the title compound, C14H13NO, the two rings show significant deviation from coplanarity, with a dihedral angle between the two planes of 49.40 (5)°. The hydroxy group is involved in an intermolecular O—H...N hydrogen bond, forming an extended one-dimensional zigzag chain along (001).

In the title compound, C13H10BrNO, the benzene ring planes are inclined at an angle of 48.85 (17)°, resulting in a nonplanar molecule. A characteristic of aromatic Schiff bases with N-aryl substituents is that the terminal phenyl rings are twisted relative to the HC=N plane. In this case, the HC=N unit makes dihedral angles of 11.1 (4) and 38.5 (3)° with the hydroxybenzene and bromobenzene rings, respectively. In the crystal, the molecules are linked by O—H...N hydrogen bonds to form infinite (C8) chains along the b axis.

In the title compound, C16H17N3O2S·H2O, the triazole ring makes a dihedral angle of 34.63 (6)° with the benzene ring. The thiophene ring is disordered over two orientations [occupancy ratio = 0.634 (4):0.366 (4)] which make dihedral angles of 54.61 (16) and 54.57 (31)° with the triazole ring. Intermolecular N—H...O and O—H...O hydrogen bonds stabilize the crystal structure.

The title compound, C15H12ClNO, is a functionalized 1,2-benzoxazole with a chloro(phenyl)methyl substituent. The molecule is V-shaped, the dihedral angle between the mean plane of the 1,2-benzoxazole system [maximum deviation = 0.023 (3) Å for the N atom] and the phenyl ring being 70.33 (14)°. There are no hydrogen-bonding interactions in the crystal structure, which is stabilized by van der Waals interactions only.

In the title compound, 2C8H20N+·2C4H5O6−·C4H6O6·H2O, the presence of the two tetraethylammonium cations is balanced by two hydrogen l-tartrate anions. Also present in the asymmetric unit are a molecule of l-tartaric acid and a water molecule. The various components are linked by O—H...O hydrogen bonds. In the crystal, two-dimensional networks are formed via O—H...O hydrogen bonds and C—H...O interactions involving the water molecule, the hydrogen l-tartrate anions and the l-tartaric acid molecules. These layers, which stack along [001], are separated by tetraethylammonium cations. The latter are also involved in C—H...O interactions with the anions and the l-tartaric acid and water molecules participating in the two-dimensional network.

In the title compound, C14H17N5S·H2O, the triazole ring makes dihedral angles of 48.15 (8) and 84.92 (8)° with the imidazole and thiophenyl rings, respectively. The water molecule is involved in intermolecular O—H...N hydrogen bonding.