Determination of the phase diagram for the crystallization of L‐asparaginase II by a turbidity technique

Phase diagrams including the metastable zone width for the L‐asparaginase II from Escherichia coli with both PEG₆₀₀₀ and ethanol as a precipitant agent were determined, respectively. A turbidity technique giving results of nucleation and solubility limits in hours rather than in days was introduced. For the first time such data necessary for designing and controlling of crystallization processes of L‐asparaginase II are presented. Since the catalytical activity is an important parameter for L‐asparaginase II as an enzyme, a new type of phase diagram plotting the enzymatic activity as a function of temperature was established as well. Additionally, the crystalline L‐asparaginase II crystals with different shapes that formed in PEG₆₀₀₀ and ethanol, respectively, were also investigated by X‐ray Powder Diffraction (XRPD).     

Reply to “Comments on papers reporting IR‐spectra and other data of L‐alanine alaninium nitrate and L‐alanine sodium nitrate crystals” by M. Fleck and A. M. Petrosyan

The formation of the new compounds of L‐alanine alaninium nitrate and L‐alanine sodium nitrate has been presented with adequate explanation with the aid of the FTIR, XRD and NLO measurements as a reply to “Comments on papers reporting IR‐spectra and other data of alleged L‐Alanine Alaninium Nitrate and L‐Alanine sodium nitrate crystals by M. Fleck and A.M. Petrosyan” (Cryst. Res. Technol. 44 , 769, 2009). The variation in the lattice parameters, physical properties, chemical properties and nonlinear optical behaviour from the L‐alanine ensures the formation of the new compounds L‐alanine alaninium nitrate and L‐alanine sodium nitrate. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of L‐lysine monohydrochloride dihydrate (L‐LMHCl) single crystal

A nonlinear optical crystal of L‐lysine monohydrochloride dihydrate (L‐LMHCl) was grown by slow evaporation solution growth technique using deionised water and mixed solvents of deionised water and ethanol. The functional groups and vibrational frequencies were identified using FTIR and FT‐RAMAN spectra analyses. Also, the presence of hydrogen and carbon atoms in the grown sample was confirmed using proton and carbon NMR spectra analyses. Using TG‐DTA analyses, the decomposition temperature was obtained. Transmittance of the grown crystals was analysed using UV‐visible spectrum. The mechanical strength of the grown crystals was found using Vicker's microhardness tester. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of L‐valine ‐ a nonlinear optical crystal

The growth of a new nonlinear optical material L‐valine by solvent evaporation method is reported here. To grow good quality crystals pH value of growth solution has been optimized and solubility of L‐valine in different solvents and different pH values was determined. The grown crystals were characterized by IR, single crystal XRD, DTA and TGA, optical transmission and second harmonic generation (SHG) efficiency measurement. SHG efficiency of L‐valine was found equivalent to KDP and its transmission is 75%‐80% from ultraviolet to near IR region. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Observation of the δ to ε Zr‐hydride transition by in‐situ synchrotron X‐ray diffraction

We investigate the formation and dissolution of hydrides in commercially pure zirconium powder in‐situ using high‐energy synchrotron X‐ray radiation. Experimental results showed a continuous phase transition between the δ and ε zirconium hydride phases with indication of a second order phase transformation.     

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     

Crystal and Molecular Structure of bis[diaaqua(1H‐cyclopenta(2,1‐b:3,4‐b')(dipyridine ‐2,5‐dione))N ickel(II)]dihydrate

The title compound [Ni(CPDD)(H₂O)₂]₂(H ₂O )₂, {]Ni₂(C₄₄H₂₈N₈O₁₂)] (H₂O)₂ }, where CPDD = 1H‐cyclopenta(2,1‐b:3,4‐b')(dipyridine‐2,5‐dione) has been prepared and its crystal structure determined by single crystal X‐ray diffraction at room temperature. The complex crystallizes in the triclinic space group P1 w ith two molecules in the asymmetric unit. The cell dimensions are a=10.452(1),b=14.098(1) & c=16.023 Å; D=110.13(1), E=100.63(1) & J=100.85(1)°. The two independent molecules in the asymmertic unit are related by pseudo two fold symmetry. In both the molecules the coordination environment around the Ni(II) may be best described as a distorted octahedral. Due to some delocalization of charge towards one of the oxygens(O1a) from the O2a atom some degree of bond localization has been observed. The individual diones of both the molecules are almost right angles at the metal atom. A long the y‐axis inversion related molecules are forming pseudo‐dimers through hydrogen bonding.     

Time and temperature induced phase transformation in L‐isoleucine hydrochloride monohydrated crystal

Semi organic crystals have been intensively studied aiming applications in nonlinear optical (NLO). Such applicability requires crystals with both high quality and thermal stability, which make the full characterization of this material a topic issue. In this paper, single crystals of L‐isoleucine hydrochloride monohydrated (L‐Ile.H2O.HCl) was synthesized by slow evaporation technique and characterized by thermal analysis and X‐ray diffraction (XRD) measurements. XRD results at 298 K showed that the sample crystallize with the orthorhombic structure, and the lattice parameters obtained by Rietveld refinement were a = 5.873(3) Å, b = 24.814(4) Å, and c = 6.873(5) Å. Thermal analysis measurements shows four decomposition stages between 328 ‐480 K which were associated with loss of water by desolvation, loss crystallization water and decomposition of L‐Ile.HCl. XRD measurements as a function of temperature up to 428 K show an irreversible phase transformation. This transformation was obtained after 32 hours keeping the L‐Ile.HCl.H2O sample at 413 K. The analysis shows that phase transformation occurs due to water and chlorine losses without destroy the amino acid carbon chain and in the end of transformation only the precursor amino acid remains. L‐Ile.HCl.H2O present low thermal stability and the phase transformation is time and temperature dependent.     

Crystal structure and characterization of a novel organic optical crystal: 4‐chloro‐3‐nitrobenzophenone

Single crystals of a novel organic material, 4‐Chloro‐3‐Nitrobenzophenone (4C3N) were grown from acetone solution employing the technique of controlled evaporation. 4C3N belongs to the Orthorhombic system, with a = 12.9665(11) Å, b = 7.4388(6) Å, c = 24.336(2) Å, α = β = γ = 90°. FT‐IR study has been performed to identify the functional groups. The transmittance of 4C3N has been used to calculate the refractive index n; the extinction coefficient K and both the real ε_r and imaginary ε_i components of the dielectric constant as functions of photon energy. The optical band gap of 4C3N is 2.7 eV. Thermo gravimetric analysis and differential thermal analysis have also been carried out, and the thermal behavior of 4C3N crystal has been studied. The mechanical properties have been investigated. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Simple coating technique for 2‐dimensional zinc oxide nanostructure

We report a novel and simple solution‐based technique for depositing 2‐D zinc oxide platelets at low temperature. Nanoplatelets that were mostly a‐oriented associated with the Lotgering orientation factor of 0.65 were obtained by locating a glass substrate at a distance of about 5cm over the aqueous vapour of the boiling precursor. Experiments were carried out to optimize the coating parameters by placing the substrate at different positions, durations and the pH of the precursor. The X‐ray diffraction studies confirmed the structure associated with the crystallites to be wurzite. The different morphology of the zinc oxide films and blue light emission were observed using scanning electron microscopy and fluorescence spectroscopy respectively.     

Crystal structure and optical properties of 4‐nitrophenyl 4‐butoxybenzoate

The title compound, C₁₇H₁₇N₁O₅, has been synthesized and characterized by single crystal X‐ray analysis and UV‐Vis spectra. The crystals are monoclinic, P 2₁/c, a = 17.994 (5) Å, b = 4.0592 (9) Å, c = 21.625 (5) Å, β = 99.634 (5)°, V = 1557.2 (6) ų and Z = 4. The molecule has an almost stretched form with a molecular length of 17.505 Å and an imbricated structure known for liquid crystals. The structure contains no direction‐specific intermolecular interactions like aromatic π‐π stacking and C‐H… π(arene) other than two weak C‐H…O hydrogen bonds. Good optical transmittance in the entire visible region of the UV‐Vis spectrum suggests that it is a potential candidate for optoelectronic applications. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Crystal and Molecular Structure of (μ‐terephthlato) bis [(N‐Salicylidene ‐N'‐(2‐hydroxyethyl) ethylenediamine) Copper(II)]

The title compound [[Cu(shen)]₂(tp)], {[Cu(C₁₅H₁₇O₄N₂)]2}, where tp = dianion of terephthalic acid and shen = (N‐salicylidene‐N'‐(2‐hydroxyethyl ethylene‐diamine)) has been prepared and its crystal structure determined by single crystal X‐ray diffraction at room temperature. The complex crystallizes in the orthorhombic space group Pbca with four formula units in a unit cell of dimensions a = 12.298(2), b = 14.214(2) and c = 16.436(2)Å. The structure consists of binuclear units with Cu(II) ion bridged by the tp ligand in a bis‐unidentate fashion. The five coordinate Cu(II) complex adopts a distorted square‐based pyramid. A crystallographic inversion center has been located at the center of the benzene ring of the tp bridging ligand. The Cu … Cu distance inside a same binuclear entity is 11.069Å. Intermolecular aromatic ring stacking interactions were observed with the shortest atom to atom contact being 3.423Å.     

X‐ray Rotation‐Tilt‐Method — First Results of a new X‐ray Diffraction Technique

That from us as X‐ray Rotation‐Tilt Technique (XRT Method) designated procedure principle represents a world innovation and overcomes essential disadvantages of comparable diffraction techniques known up to now. Starting from the origin and the informational content of the XRT interferences a realization of a special equipment and selected examples of some first applications are presented.     

Growth and characterization of 4‐Aminopyridinium‐4‐nitro phenolate single crystals

Organic optical material 4‐Aminopyridinium‐4‐nitro phenolate (4AP4NP) has been synthesized, and single crystals of size 20 x 14 x 6 mm³ have been grown from acetone solvent at room temperature by solvent evaporation technique. The grown crystals have been characterized by X‐ray diffraction to determine the cell parameters, and by FT‐IR technique to confirm the formation of the expected compound. The crystal belongs to monoclinic crystal system with space group P2₁/a.The structural perfection of the grown crystals has been analyzed by high‐resolution X‐ray diffraction (HRXRD) rocking curve measurements. The thermal stability of the compound has been determined by TG‐DTA curves. The transmittance of 4AP4NP has been used to determine the refractive index n; the extinction coefficient K and both the real ε_r and imaginary ε_i components of the dielectric constant as functions of photon energy. The optical band gap of 4AP4NP is 2.4 eV. The dielectric and mechanical behavior of the specimen was also studied. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Application of diffusion couple technique for the determination of the Ti‐Bi‐Sn phase diagram

The system Ti‐Bi‐Sn has been investigated by solid/liquid diffusion couples at 500, 600, 700 and 800°C. A non‐negligible solubility of Sn into solid Bi is found. Diffusion layers of the recently revealed ternary compound Ti₃BiSn have been observed, thus its existence has been confirmed. Data about the homogeneity ranges of the binary end‐system compounds have been obtained. The assessed growth constants of the diffusion layers are comprised in the interval 10^‐12 –10^‐14 m².s^‐1. The phases participating in the hypothetical ternary eutectic reaction, probably are: (Bi), (Sn), Liquid and Ti₂Sn₃. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of the nonlinear optical crystal: L‐arginine trifluoroacetate

Single crystal growth of the organic nonlinear optical crystal, L‐arginine trifluoroacetate (L‐Arg·CF₃COOH, abbreviated as LATF) is reported. Low temperature solution growth method is employed for the growth of bulk single crystals. The cell parameters are verified by single crystal diffraction. Fourier transform infrared (FT‐IR) and Fourier transform Raman analysis are used to confirm the presence of various functional groups in the grown crystal. The thermal properties of the grown crystals are studied by thermogravimetric analysis and differential scanning calorinetry analysis (TGA/DSC). Second harmonic generation (SHG) measurement confirms the NLO properties of the grown crystal. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Quantitative Determination of Crystalline Na5P3O10 –I (Form‐I) in Commercial Tripolyphosphate using X‐ray Diffraction Patterns

An x‐ray diffraction method (XRD) for quantitative determination of the crystalline Na₅P₃O₁₀‐I (Form‐I) in a mixture of Form‐I/Form‐II was applied for commercial pentasodium tripolyphosphate analysis. The XRD pattern of the Form‐I shows the unique non‐overlapping 2θ peak at a position of ≈ 21.8 deg. and also at ≈ 29.0 deg. (Cu radiation). The area (integral of the intensity) under the peaks is proportional to the amount of the Form‐I in the mixture covering the range up to 100 wt.%. That enables one to obtain a calibration line and to determine the amount of Form‐I in the mixture of Form‐I/Form‐II and also in commercial pentasodium tripolyphosphate. Commercial samples with high Form‐I concentration, in case they are contaminated with sodium pyrophosphate (Na₄P₂O₇), should be diluted with Form‐II to bring the concentration of the Form‐I below 50 wt.% in the analysed sample.     

Preparation,single crystal growth and characterization of bis(tetrabutylammonium)bis(4,5‐dithiolato‐1,3‐dithiole‐2‐thione)copper

The preparation and single crystal growth of bis(tetrabutylammonium)bis(4,5‐dithiolato‐1,3‐dithiole‐2‐thione)copper, (I), are described. The energy gap Eg of (I) is about 2.38 eV. The nonlinear optical susceptibility χ⁽³⁾ is about 1.3×10^‐3 esu at 1064 nm. The characterization of (I) has been performed by electronic absorption, infrared and X‐ray powder diffraction spectroscopy. The thermal behavior of (I) has been investigated by means of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements in air. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis,crystal structure and third order nonlinear optical properties of bis(tetra‐n‐propylammonium) bis(2‐thioxo‐1,3‐dithiole‐4,5‐dithiolato)cuprate(II)

A novel bis (dmit) complex of copper (II), [(C₃H₇)₄N]₂[Cu(dmit)₂] ( 1 ), where dmit is 2‐thioxo‐1,3‐dithiole‐4,5‐dithiolate, was prepared and structurally characterized by X‐ray single crystal diffraction. The copper (II) atom is tetracoordinated by four dmit S atoms, forming a nearly square planar arrangement. The [Cu(dmit)₂]^2‐ anions and the [(C₃H₇)₄N]⁺ counter‐cations form a three‐dimensional solid‐state structure by C–H…S hydrogen bonds. The third‐order nonlinear optical properties of the complex were determined by picosecond Z‐scan technique at a wavelength of 1064 nm. The results indicate the compound exhibits reverse saturation absorption and self‐defocusing performance. The molecular second‐order hyperpolarizability γ is calculated to be as high as (1.8±0.2)×10^‐30 esu. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and X‐ray powder diffraction studies of semiconducting alloys in the system AgCd2‐xZnxGaS4

X‐ray powder technique was used in the investigation of AgCd₂GaS_4–'AgZn₂GaS₄' section to determine the region of AgCd₂GaS₄‐based solubility. It was established that the solid solution forms up to 75 mol.% 'AgZn₂GaS₄'. The refinement of AgCd_0.5Zn_1.5GaS₄ structure was performed. This alloy crystallizes in orthorhombic structure (space group Pmn2₁ ) with unit cell parameters a =0.78772(2), b =0.67221(2), c =0.64019(2) nm, V =0.33899(3) nm³. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)