T. Uma Devi

Growth and characterization of glycine picrate single crystal.

Glycine picrate (GP), an organic material, was synthesized and successfully grown by solution growth method. Cell parameters of the grown crystals were obtained from the single crystal X-ray diffraction analysis and the presence of functional groups was identified by FTIR study. Its optical properties were examined by UV-vis-NIR analysis, which shows that the crystal is transparent between the wavelengths 400 nm and 1000 nm. Thermal analysis carried out for the glycine picrate reveals that the crystal exhibits a single sharp weight loss at 214 degrees C. The fluorescence spectrum of glycine picrate was recorded. The Vickers microhardness values were measured for the grown crystal.

Growth of ninhydrin single crystal and its characterization

A novel organic nonlinear optical crystal ninhydrin having good optical quality was grown by solution technique using aqua solution. The quality of the crystal was also examined by high-resolution X-ray diffraction study. Solubility studies were made at different temperatures. Functional groups present in the grown material were identified from the vibrational frequencies of recorded FTIR spectrum. Transmittance of the crystal was recorded using the UV-vis-NIR spectrophotometer. From the thermal analysis it was observed that the material exhibits single sharp melting point. The fluorescence spectrum of ninhydrin was recorded. The Vickers microhardness values were measured for the grown crystal. Second harmonic generation conversion efficiency estimated using Kurtz and Perry method is about five times that of KDP.

Spectral, thermal and optical properties of l-tryptophanium picrate: A nonlinear optical single crystal

A new organic nonlinear optical material L-tryptophanium picrate was synthesized. From the powder XRD pattern the various planes of reflections were identified. The grown crystals were subjected to FT-IR and (1)H NMR spectral analyses to confirm the synthesized compound. Thermal properties of the crystals were investigated using thermo gravimetric (TG) and differential thermal analyses (DTA). The second harmonic generation (SHG) efficiency of the title compound was found using the modified experimental setup of Kurtz and Perry.

Ultrafast optical nonlinearity, electronic absorption, vibrational spectra and solvent effect studies of ninhydrin

FT-IR, FT-Raman and UV-Vis spectra of the nonlinear optical molecule ninhydrin have been recorded and analyzed. The equilibrium geometry, bonding features, and harmonic vibrational wavenumbers have been investigated with the help of B3LYP density functional theory method. A detailed interpretation of the vibrational spectra is carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology. Solvent effects have been calculated using time-dependent density functional theory in combination with the polarized continuum model. Natural bond orbital analysis confirms the occurrence of strong intermolecular hydrogen bonding in the molecule. Employing the open-aperture z-scan technique, nonlinear optical absorption of the sample has been studied in the ultrafast and short-pulse excitation regimes, using 100 fs and 5 ns laser pulses respectively. It is found that ninhydrin exhibits optical limiting for both excitations, indicating potential photonic applications.

Synthesis, growth, structure and spectroscopic characterization of a new organic nonlinear optical hydrogen bonding complex crystal: 3-carboxyl anilinium p-toluene sulfonate.

A new organic nonlinear optical hydrogen bonding complex salt of 3-carboxyl anilinium p-toluene sulfonate has been synthesized and highly transparent good quality single crystals of it were successfully grown employing slow solvent evaporation solution growth technique at ambient temperature. The (1)H and (13)C NMR spectra were recorded to establish the molecular structure. The single crystal XRD analysis carried out reveals that the title salt crystallizes in monoclinic crystal system with non-centrosymmetric P2₁ space group. The FT-IR spectrum was recorded to confirm the presence of various functional groups in the grown title crystal. The UV-Vis-NIR transmission spectrum was recorded to apprehend the suitability of the single crystal of the title salt for various optical and NLO applications. The TG/DTA thermal analysis was performed to establish the thermal stability of the crystal. The SHG activity in the grown crystal was identified employing the modified Kurtz-Perry powder test. The electronic charge distribution and reactivity of the molecules within the title complex was studied by HOMO and LUMO analysis and the molecular electrostatic potential (MEP) of the title crystal was performed using the B3LYP method.

Crystal growth, spectral, optical and thermal properties of semiorganic nonlinear optical material: Picolinic acid hydrochloride

The bulk single crystal of 2-picolinic acid hydrochloride (PHCL) (a semi-organic nonlinear optical material of dimensions 25×15×10 mm(3)) was successfully grown by slow solvent evaporation technique. The XRD results revealed the cell parameters and the centrosymmetric nature of the crystal structure. FT-IR spectral study identified the functional groups, nature of bonding and their bond strength. The UV-Vis-NIR studies recognized the optical transmittance window and the lower cut off wavelength of the PHCL crystal and thus it could be performed as a NLO material. (1)H NMR and (13)CNMR spectra were correlated with the XRD standard for the molecular structure reveals harmony of the materials. Thermal properties of the crystal were studied by thermo gravimetric analysis (TGA) and differential thermal analysis (DTA); the derived kinetic parameter values support the intuitive association of picolinicacid and HCl leads to the spontaneous formation of PHCL with a first order reaction. The presence of a proton and a proton acceptor groups provide the necessary stability to induce charge asymmetry in the PHCL structure. The load dependent hardness values of the crystal were measured by microhardness testing.

Synthesis, growth, spectral and thermal properties of a new organic crystal: 2-carboxypyridin-1-ium trichloroacetate.

A novel organic optical material complex of 2-carboxypyridin-1-ium trichloroacetate has been synthesized and crystals were grown from aqueous solution employing the technique of controlled evaporation. The crystal structure has been determined using single crystal X-ray diffraction studies. The single crystals were successfully grown by the slow evaporation method with dimensions 12 × 8 × 3 mm(3). FT IR spectral investigation has been carried out to identify the various functional groups present in the grown crystal. Molecular structure was confirmed by NMR spectral analysis. Melting point was found using thermal measurements.

Synthesis, structural elucidation and spectroscopic analysis of 3a,8b-dihydroxy-4-oxo-1H,2H,3H,3aH,4H,8bH-indeno[1,2-d]imidazolidin-2-iminium chloride.

Ninhydrin guanidinium chloride (3a,8b-dihydroxy-4-oxo-1H,2H,3H,3aH,4H,8bH-indeno [1,2-d]imidazolidin-2-iminium chloride) a semiorganic crystal was synthesized. The structure was determined using X-ray single crystal technique. Comparisons between the FT-IR spectrum of ninhydrin guanidinium chloride with ninhydrin were made. Melting point was found using thermal measurements. The molecular geometry, vibrational frequencies and Mulliken charges of the compound in the ground state have been calculated by the density functional theory (DFT) method with 3-21G(d,p) basis set and theoretical frequencies were compared with the experimental FT-IR spectrum. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, natural bond orbitals (NBO) and thermodynamic properties at various temperatures of the compound were investigated by theoretical calculations.

Growth, structure, spectral and optical properties of semiorganic crystal: Pyridine-1-ium-2-carboxylatehydrogenbromide.

Pyridine-1-ium-2-carboxylatehydrogenbromide (PHBr) crystal was grown from aqueous solution by slow evaporation method. The calculated lattice parameters of single crystal X-ray diffraction have shown the triclinic crystal system with centrosymmetric space group of Pī. The interaction of functional groups and their importance in their application was identified by FTIR spectral analysis. The material is optically transparent and the grown crystal is having lower cut off wavelength as 294nm, thereby confirming the enhancement of non-linear optical (NLO) property and optical band gap of the PHBr have been determined as 2.49eV by UV-Vis-NIR studies. The (1)H NMR spectrum confirms the molecular structure and the presence of different kinds of protons.