P. Praveen Kumar

Growth and Characterization of Benzimidazolium Salicylate: NLO Property from a Centrosymmetric Crystal

A new organic charge transfer molecular complex salt of benzimidazolium salicylate (BSL) single crystals was grown by the slow evaporation solution growth technique using methanol as a solvent at room temperature. The grown crystals were characterised by single crystal X-ray diffraction (XRD) which confirms that the crystal belongs to monoclinic system with the centrosymmetric space group P21/. The crystalline perfection of the grown crystal was analyzed by high resolution X-ray diffraction (HRXRD). The presence of various functional groups was identified by FTIR spectrum. UV-Vis spectral study reveals that the BSL crystal is optically transparent in the wavelength region 342 nm–1100 nm. Dielectric measurements of the crystal at various frequencies were also determined. The mechanical properties of the grown crystal were assessed using Vickers microhardness testing. Nonlinear optical property of the crystal was confirmed using Kurtz and Perry powder technique and the SHG efficiency of the BSL crystal is 0.7 times greater than that of the standard KDP crystal.

Crystal structure of 2,5-di­methyl­anilinium salicylate

The title molecular salt, C8H12N+·C7H5O3 − arose from the proton-transfer reaction between 2,5-xylidine and salicylic acid. In the anion, the dihedral angle between the planes of the aromatic ring and the –CO2 − group is 11.08 (8)°; this near planarity is consolidated by an intramolecular O—H⋯O hydrogen bond. In the crystal, the components are connected by N—H⋯O hydrogen bonds, with all three O atoms in the anion acting as acceptors; the result is a [100] chain. The structure also features weak C—H⋯O bonds and aromatic π–π stacking [centroid-to-centroid distance = 3.7416 (10) Å] interactions, which lead to a three-dimensional network.

Optical, Thermal, and Mechanical Properties of L-Serine Phosphate, a Semiorganic Enhanced NLO Single Crystal

Single crystals of L-serine phosphate (LSP) were grown by slow evaporation technique. The optical studies reveal the transparency of the crystal in the entire visible region. Grown crystal was subjected to single crystal XRD diffraction technique. Thermal studies of LSP confirm the thermal stability of the crystal and it is stable up to 210°C. The functional groups and optical behaviour of the crystal were identified from FT-IR and UV-Vis analysis. The crystals were also characterized by microhardness and photoconductivity to determine the mechanical strength and the optical conductivity. Laser damage threshold and nonlinear optical activity of the grown crystal were confirmed by Q-switched Nd : YAG laser beam.

Crystal structure of benzimidazolium salicylate.

In the anion of the title molecular salt, C7H7N2 +·C7H5O3 − (systematic name: 1H-benzimidazol-3-ium 2-hydroxybenzoate), there is an intramolecular O—H⋯O hydrogen bond that generates an S(6) ring motif. The CO2 group makes a dihedral angle of 5.33 (15)° with its attached ring. In the crystal, the dihedral angle between the benzimidazolium ring and the anion benzene ring is 75.88 (5)°. Two cations bridge two anions via two pairs of N—H⋯O hydrogen bonds, enclosing an R 4 4(16) ring motif, forming a four-membered centrosymmetric arrangement. These units are linked via C—H⋯O hydrogen bonds, forming chains propagating along the b-axis direction. The chains are linked by C—H⋯π and π–π interactions [inter-centroid distances = 3.4156 (7) and 3.8196 (8) Å], forming a three-dimensional structure.

Systematic analysis of CuO and Co doped CuO nanoparticles and the impact of dopant on magnetic and optical properties

The pure and Co doped CuO nanoparticles were synthesized by wet chemical method at different molar ratios. The crystallinity of CuO and Co doped CuO nanoparticles were studied by X Ray Diffraction analysis. The cubic structure of the synthesized nanoparticles was identified to be face centered cubic (f c c) and the average grain size of pure and Co doped CuO nanoparticles was calculated using Debye Scherrer formula. The particle size of the as synthesized nanoparticles was verified using Field Emission SEM. The magnetic influence of Co on CuO nanoparticles was analysed using VSM measurements and the result was compared with CuO nanoparticles. It was noted that the magnetisation value (Ms) of Co doped CuO (Ms=0.07009 emu/g) was higher when compared with pure CuO (Ms=0.0149 emu/g) nanoparticles. The optical activity of the sample was studied under UV-DRS. The band gap energy was calculated using Kubelka-Munk function and the result indicated that CuO (Eg=2.78 eV) has better optical activity than Co doped CuO (Eg=2.98 eV) nanoparticles.The pure and Co doped CuO nanoparticles were synthesized by wet chemical method at different molar ratios. The crystallinity of CuO and Co doped CuO nanoparticles were studied by X Ray Diffraction analysis. The cubic structure of the synthesized nanoparticles was identified to be face centered cubic (f c c) and the average grain size of pure and Co doped CuO nanoparticles was calculated using Debye Scherrer formula. The particle size of the as synthesized nanoparticles was verified using Field Emission SEM. The magnetic influence of Co on CuO nanoparticles was analysed using VSM measurements and the result was compared with CuO nanoparticles. It was noted that the magnetisation value (Ms) of Co doped CuO (Ms=0.07009 emu/g) was higher when compared with pure CuO (Ms=0.0149 emu/g) nanoparticles. The optical activity of the sample was studied under UV-DRS. The band gap energy was calculated using Kubelka-Munk function and the result indicated that CuO (Eg=2.78 eV) has better optical activity than Co doped Cu...

Investigation on growth, optical, thermal, mechanical and dielectric studies of Benzimidazolium L-aspartate NLO crystal

ABSTRACT The organic salt of Benzimidazolium L-aspartate (BLA) has been synthesised and single crystals were grown by slow evaporation solution growth technique at room temperature using water as the solvent. The grown crystal was subjected to single crystal X-ray diffraction analysis and confirmed it belongs to monoclinic crystal system with space group P21/c. The crystalline perfection was studied using High resolution X-ray diffraction (HRXRD). The functional groups were analysed by FT-IR analysis. The optical transmittance and the lower cut-off wavelength of the BLA crystal have been identified by UV-Vis study. The thermal stability of the title crystal was investigated by TGA/DTA analyses. The Vickers microhardness analysis was carried out to study the mechanical strength of the crystal. The dielectric response of the crystal was studied in the frequency range 100 to 5 MHz at different temperatures. The surface morphology of the grown BLA crystal was studied by scanning electron microscopy (SEM). The second harmonic generation efficiency was measured in comparison with KDP by employing Kurtz Perry Powder method.

Crystal growth, perfection, linear and nonlinear optical, photoconductivity, dielectric, thermal and laser damage threshold properties of 4-methylimidazolium picrate: an interesting organic crystal for photonic and optoelectronic devices

The 4-methylimidazolium picrate has been synthesized and characterized successfully. Single and powder x-ray diffraction studies were conducted which confirmed the crystal structure, and the value of the strain was calculated. The crystal perfection was determined by a HRXR diffractometer. The transmission spectrum exhibited a better transmittance of the crystal in the entire visible region with a lower cut-off wavelength of 209 nm. The linear absorption value was calculated by the optical limiting method. A birefringence study was also carried out. Second and third order nonlinear optical properties of the crystal were found by second harmonic generation and the z-scan technique. The crystals were also characterized by dielectric measurement and a photoconductivity analyzer to determine the dielectric property and the optical conductivity of the crystal. The laser damage threshold activity of the grown crystal was studied by a Q-switched Nd:YAG laser beam. Thermal studies established that the compound did not undergo a phase transition and was stable up to 240 °C.

Bis(creatininium) 3-nitro­phthalate monohydrate

In the title hydrated molecular salt, 2C4H8N3O+·C8H3NO62−·H2O, the dihedral angles between the benzene ring and the nitro group and the carboxylate groups are 48.0 (2), 55.3 (2) and 60.7 (2)°, respectively. In the crystal, the components are linked by N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, generating a two-dimensional network parallel to (102).