Crystal growth,thermal and optical studies of L‐histidine tetrafluoroborate: A semiorganic NLO material

L‐histidine tetrafluoroborate (L‐HFB), a semiorganic nonlinear optical (NLO) material has been synthesized and characterized by elemental analysis and FT–NMR spectroscopic studies. Solubility of L‐HFB has been determined in water and ethanol. The single crystals with dimensions 15 x 12 x 3 mm³ were grown by slow evaporation technique under two different pH conditions. The effect of pH on the morphology of the crystals have been studied. The grown crystals of both pH values has been subjected to single crystal X‐ray diffraction to determine the unit cell dimensions and morphology. The thermal stability has been analyzed by TGA and DTA. The microhardness test was carried out in (001) plane and the hardness coefficient was calculated. The birefringence values (Δ_n) were determined in the wavelength region 5540–6460 Å. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal growth,thermal, optical and microhardness studies of tris (thiourea) zinc sulphate - a semiorganic NLO material

Tris (thiourea) zinc sulphate (ZTS), a semiorganic nonlinear optical (NLO) material has been synthesized at 30 °C. The solubility was determined in different solvents such as water, ethanol and water mixture of ethanol (1:1). Good quality single crystals with size 10 × 8 × 6 mm³ were grown by slow evaporation technique within three weeks with approximate growth rate of 0.5 mm/day. The grown crystals have been subjected to single crystal X-ray diffraction to determine the unit cell dimensions and morphology. The TGA and DTA reveal that the material has good thermal stability. The UV-Vis spectrum shows that the material has wide optical transparency in the entire visible region. The second harmonic generation was confirmed by Kurtz powder method. The birefringence of the crystal was measured in the visible region and it was found to vary with the wavelength. The microhardness test was carried out in (100) plane and the load dependent hardness was measured. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Spectral studies of methyl‐p‐hydroxy benzoate: An organic nonlinear optical crystalline material

The single crystals of Methyl‐p‐Hydroxy Benzoate (MHB) were grown by solution growth technique and characterized by X‐ray diffraction (single crystal), density, melting point, UV‐Vis, FT‐IR and FT‐Raman techniques. Electron Paramagnetic Resonance (EPR) spectra of Cu²⁺: MHB were recorded and the spin Hamiltonian parameters were evaluated. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth,structural, thermal and optical studies on L‐glutamic acid hydrobromide – A new semiorganic NLO material

A new semiorganic crystal, L‐glutamic acid hydrobromide, C₅H₁₀NO₄Br (GHB) has been grown from aqueous solution. The single crystal X‐ray analysis of the crystal showed that it belongs to the non‐centrosymmetric P2₁2₁2₁ space group with protonated glutamic acid as cation and bromine as anion. The back‐bone conformations of the amino acid are in cis and trans form. The side‐chain conformations are observed to be in gauche I / trans / cis / trans forms. The characteristic ‘head‐to‐tail’ hydrogen bonding interaction is observed through a chain C(5) motif. Further, the crystal structure is stabilized by an intricate three‐dimensional hydrogen bonding network. TGA/DTA showed that the grown crystals are thermally stable upto 219 °C without any phase transition. The functional groups responsible for the various modes of vibrations were identified by using FTIR spectroscopy. UV‐Vis‐NIR spectra showed that the crystals have excellent transparency in the visible and infrared regions. The second harmonic generation (SHG) conversion efficiency was investigated to explore the NLO characteristics of the material. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Vibrational,optical and microhardness studies of trimethoprim DL ‐malate

Trimethoprim malate, an organic crystal, has been synthesized using slow evaporation method from its aqueous solution. Structural, optical and the mechanical properties of the grown crystal have been investigated by various characterization techniques which include FTIR spectra, single crystal XRD, UV‐Vis spectra and Vickers microhardness testing. The structure of the compound predicted by analysing the recorded FTIR spectrum compliments the structure determined using single crystal X‐ray diffraction. Single crystal X‐ray diffraction study reveals that the crystals are monoclinic [P2₁/c, a=12.9850 Å, b=9.3038 Å, c=15.6815 Å and β=111.065°]. The UV‐Vis spectrum exhibits maximum transparency (98%) for a wide range suggesting the suitability of the title compound for optical applications. The optical constants have been calculated and illustrated graphically. Microhardness tests have been performed on the cystal under study and the Vicker hardness number has been calculated. The work hardening coefficient is found to be 2.85 which suggest that the crystal belongs to the family of soft materials. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Structural and thermal characterization of L‐arginine dihydrate ‐ a nonlinear optical material

Crystal structure and thermal stability of the hydrated crystals of the basic amino acid L‐arginine named as L‐arginine dihydrate (LAD), a nonlinear optical material have been reported here. The title compound crystallized in the space group P2₁2₁2₁ with Z=4 and unit cell dimensions a=11.856(2)Å, b=15.694(2)Å, c=5.664(3)Å. The arginine molecule is a zwitterion with the guanidyl group accepting an extra proton from the carboxylate group. DTA‐TG analysis gives an idea about the thermal behaviour of LAD and ruled out the possibility of structural changes independent of mass changes. © 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

Single crystal growth and properties of semiorganic nonlinear optical L‐arginine hydrochloride monohydrate crystals

L‐arginine hydrochloride monohydrate (LAHCl.H₂O) has been synthesized and single crystals have been grown from its aqueous solution by slow evaporation and slow cooling methods. The solubility of the material was measured at various temperatures and bulk crystals of size 26×13×11 mm³ have been grown by optimizing the growth parameters. The grown crystals have been subjected to single crystal XRD studies to confirm the structure and to estimate the lattice parameters. FTIR analysis indicate the mode of vibrations of different molecular groups present in LAHCl and confirm the protonation of guanidyl, amino groups and deprotonation of COO^‐ groups. UV‐Vis transmission spectrum revealed the linear optical properties of the grown crystals with a transparency of 65% over the entire visible range upto 300 nm. Thermal behavior of the grown crystal was investigated from DTA and TGA measurements. Dielectric studies have been carried out on the grown crystals. Kurtz and Perry powder SHG technique confirms the NLO property of the grown crystal. The SHG efficiency of LAHCl was found to be 0.38 with respect to KDP. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of a new semi organic NLO material: L‐tyrosine hydrochloride

Single crystals of L‐Tyrosine hydrochloride were grown by using the submerged seed solution method. The grown crystals were characterized by using single crystal X‐ray diffraction. Functional groups and the modes of vibrations were identified by FTIR spectroscopy. The TGA/DTA studies showed that the crystal is stable up to 232°C. Microhardness study revealed that the crystal is a hard material. It is transparent in the entire visible region. The SHG efficiency was determined by the Kurtz and Perry method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and characterization of a new nonlinear optical single crystal: L‐Lysinium trifluoroacetate

Single crystals of a new L‐Lysine salt: L‐Lysinium trifluoroacetate {abbreviated as LLyTFA; [(NH₂)‐(CH₂)₄‐CH‐(NH₃)‐(COOH)]⁺ CF₃COO^‐} were grown by slow evaporation of an aqueous solution at room temperature. The grown crystals were subjected to single crystal X‐ray diffraction, FTIR and UV‐Vis‐NIR spectrum analyses. The UV‐Vis‐NIR spectrum shows that the absorption is very less in the whole of the region from ultraviolet to near IR. The Kurtz‐Perry powder SHG measurement using a Nd:YAG laser of wavelength 1064nm confirms the frequency doubling of the crystal and its powder SHG efficiency was measured as d_eff = 0.96 d_eff (KDP). (© 2007 WILEY ‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and Characterization of a New Nonlinear Optical Crystal: Bis Thiourea Zinc Chloride

Bis Thiourea Zinc Chloride (BTZC) a new semiorganic nonlinear optical material has been synthesized. The solubility studies have been carried out in the temperature range 30°‐ 55°C. Single crystals of BTZC have been grown by slow evaporation of saturated aqueous solution at room temperature. The lattice parameters of the grown crystals have been determined by single crystal X‐ray diffraction technique. The UV‐Vis‐NIR transmittance spectrum has been recorded in the range 200‐2000 nm. The FT‐IR spectrum has been recorded in the range 400‐4000 cm^‐1 and the spectral bands have been compared with similar thiourea complexes.     

Growth of tetrakis thiourea potassium iodide as new second order optical material

A novel organometallic nonlinear optical (NLO) crystal, namely thiourea complex of tetrakis thiourea potassium iodide (TTPI), has been grown by slow evaporation solution growth technique. The harvested crystal is large in size. To our knowledge there is no report is available for the bulk size single crystal of TTPI. This material has a positive temperature coefficient and has been grown by slow evaporation solution growth technique. The grown crystal have been characterized by employing several techniques such as single crystal and powder X‐ray diffraction, FTIR, UV‐Vis‐NIR spectra, thermo gravimetric analyses respectively. Etching studies have also been carried out in order to know the surface defects on the as grown specimen of TTPI. The relative second harmonic generation efficiency have been tested by using Nd:YAG laser as source. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis,crystal structure and vibrational characterization of bis‐μ‐peroxo‐hexacarbonatodicerate(IV) complexes of rubidium and cesium

The new compounds Rb₈[Ce(O₂)(CO₃)₃]₂ · 12 H₂O (1) and Cs₈[Ce(O₂)(CO₃)₃]₂ · 10 H₂O (2) were obtained from the reaction of hydrogen peroxide and Ce(III) in saturated alkali carbonate solutions. The crystal structures and the unit cell parameters of (1) triclinic, P‐1 with a = 8.973(2) Å, b = 10.815(2) Å, c = 11.130(3) Å, α = 66.992(2)°, β = 68.337(2)°, γ = 74.639(2)°, V_EZ = 914.7(4) ų, Z = 2, and (2) orthorhombic, Pbca, a = 19.3840(16) Å, b = 18.528(2) Å, c = 10.487(3) Å, V_EZ = 3766.4(13) ų, Z = 8, were determined. Both compounds contain the bis‐µ‐peroxo‐hexacarbonatodicerate(IV)‐ion, [(CO₃)₃Ce(O₂)₂Ce(CO₃)₃]^8‐. IR and Raman spectra were measured and discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystallization and characterization of nonlinear optical l‐histidinium dihydrogen orthophosphate orthophosporic acid single crystal

L‐histidinium dihydrogen orthophosphate orthophosporic acid (abbreviated as LHP) with molecular formula C₆H₁₀N₃O₂⁺·H₂PO₄^‐·H₃PO₄ was successfully grown by slow evaporation technique from aqueous solution. The crystal was characterized by X‐ray diffractometry (XRD), UV‐Vis‐NIR, TGA, DTA, microhardness and solubility studies. The dielectric constant and dielectric loss of the crystal were studied as function of frequency. Photoconductivity studies were also carried out on the sample. The SHG efficiency of the crystal is studied using the Kurtz and Perry technique. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth,optical and thermal studies of nonlinear optical L‐arginine perchlorate single crystals

A potentially useful semiorganic nonlinear optical (NLO) material, L‐arginine perchlorate, has been synthesized and bulk crystals have been grown by slow cooling technique. The grown crystals were characterized by single crystal X‐ray diffraction, UV‐Vis‐NIR spectroscopy, FT‐IR, thermal analysis and SHG measurements. The grown crystals were thermally stable upto 153°C and exhibit SHG efficiency of about 0.17 with respect of Urea. The etching studies have been carried out on the grown crystal. LAPC has good optical transmission not only in the visible range, however, also in the near UV part of the spectra and hence it is a potential material for nonlinear frequency conversion. The refractive index was measured by the Brewster's angle method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Structural,thermal and optical characterizations of a NLO material: L‐alaninium oxalate

An organic electro‐optic and nonlinear optical (NLO) material, L‐alaninium oxalate, was synthesized by the standard method. The synthesized material was purified by repeated recrystallization. Single crystals were grown by the slow evaporation technique. The grown crystals were transparent and had optimum dimensions (20 × 3 × 2 mm³) and were characterized by single crystal XRD, FT‐NMR, FT‐IR, TGA‐DTA and UV‐Vis‐NIR techniques. The second harmonic generation (SHG) from the material was confirmed using Nd:YAG laser. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis,growth, morphology of the semiorganic nonlinear optical crystal L‐glutamic acid hydrochloride and its structural,thermal and SHG characterizations

One of the halide derivatives of L ‐glutamic acid which was identified as a semiorganic nonlinear optical material, L ‐glutamic acid hydrochloride [HOOC(CH₂)₂CH(NH₂)COOH.HCl], was grown as bulk single crystal and its significant properties were characterized. The stoichiometric title compound was synthesized and the solubility of its recrystallized form in DD water was determined in the temperature range 30–80 °C by gravimetric method. Structural confirmation was carried out by powder X ‐ray diffraction study through lattice parameter verification. Optical quality smaller dimension single crystals were grown from aqueous solution by self nucleation through slow evaporation of solvent method and a large dimension single crystal was grown by slow cooling method with reversible seed rotation technique. Morphological importances of different growth facets of the as grown crystals were studied through optical goniometry. Unit cell structure of the grown crystal was refined by single crystal X ‐ray diffraction analysis, functional groups present in the crystal responsible for various modes of vibrations were confirmed by FTIR spectroscopy analysis, thermal stability of the grown crytal was analysed by TG/DTA and DSC and second harmonic generation (SHG) of a fundamental Nd:YAG laser beam by Kurtz technique. Results indicate that the grown crystal is in stoichiometric composition and has significant improvement in its thermal and SHG properties when compared to pure L ‐glutamic acid polymorphs.     

Growth and characterization of semicarbazone of cyclohexanone

A new organic single crystal of semicarbazone of cyclohexanone (SCCH) has been synthesized and grown as a bulk single crystal by low temperature solution growth technique for the first time in the literature. The grown crystal has been confirmed by X‐ray diffraction and proton nuclear magnetic resonance spectral analyses and also characterized by FT‐ir and FT‐Raman studies. Thermal properties of the grown crystals were studied by thermogravimetric and differential thermal analyses. Optical transmittance was studied by ultraviolet‐visible spectrum and the second harmonic generation property was tested by using Q switched Nd: YAG laser as a source. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of L‐histidine hydrochloride monohydrate single crystals

Good optical quality single crystal of L‐histidine hydrochloride monohydrate (LHC) a novel semi organic NLO material was grown by slow solvent evaporation technique. The crystal was characterized by X‐ray diffractometry (XRD), Fourier Transform Infra‐red (FTIR), UV‐Vis‐NIR, TGA, DTA, microhardness and solubility studies. The SHG efficiency is found to be higher than that of KDP crystal. The dielectric constant and dielectric loss of the crystal was studied as function of frequency and the results are discussed. Photoconductivity studies were also carried out which reveals the positive photoconducting properties of the sample. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal growth,optical, mechanical and electrical properties of organic NLO material γ‐glycine

Single crystals of organic non‐linear optical material, γ‐glycine have been grown by gel method for the first time. The γ‐phase is confirmed by single crystal XRD. The presence of various functional groups of γ‐glycine are confirmed by FTIR. The UV‐Vis‐NIR spectrum reveals the high percentage of transmission of the sample in the entire visible region. The SHG of γ‐glycine is confirmed by Kurtz powder technique. TGA‐DTA studies indicate that the crystal is structurally stable upto 170 °C. Microhardness investigations are conducted on the grown crystals. The dielectric constant measurements are carried out and the nature of variation of dielectric constant ε′ and dielectric loss D in the frequency range of 50 Hz to 5 MHz is studied and reported. Photoconductivity studies of γ‐glycine crystals revealed the negative photoconducting nature. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)