Syntheses and X‐Ray crystal structures of aminated 4,4'‐Bi‐1,2,4‐triazole salts

3‐Amino‐4,4'‐bi‐1,2,4‐triazole hydrochlorate and 3,3'‐diamino‐4,4'‐bi‐1,2,4‐triazole ditosylate were obtained with the reduction of 3,3',5,5'‐tetraazide‐4,4'‐bi‐1,2,4‐triazole (TABT) by (Ph)₃P/H₂O and the followed salt forming reaction with concentrated HCl and aqueous TsOH, respectively. Their structures were characterized with elemental analyses, IR, MS, ¹H and ¹³C NMR spectra. The single crystals were cultivated and determined with X‐ray diffraction, test results reveal that H⁺ combines with electron‐rich N atom in triazole ring to form ionic salts, two N,N‐linked triazoles are almost perpendicular to each other due to lower steric hindrance. The aromatic π…π stacking interactions and hydrogen bonds between molecules are observed. These two novel salts and their derivatives may be applied in coordination chemistry, medicinal chemistry and energetic materials.     

The Crystal Structures of O,O‐Dimethylalpinumisoflavone and 5‐O‐Methyl‐4'‐O‐(3‐methyl‐but‐2‐en‐1‐yl)alpinumisoflavone

The petrol extract of the rootbark of Milletia Thonningii obtained by column chromatography afforded sixteen different crystalline samples to be isolated. The crystal structures of two of these compounds, O,O‐Dimethylalpinumisoflavone (I) and 5‐O‐Methyl‐4'‐O‐(3‐methyl‐but‐2‐en‐1‐yl)alpinumisoflavone (II) are being reported here. (II) has two independent molecules in the asymmetric unit and differs from (I) in a longer side chain attached to C(15) of the phenyl ring. The structural features of the three molecules in the title compounds are reported and compared. The derivatives, being subject of this article are the first reported crystal structures where the isoflavone fragment is fused to a further six membered ring that results in a tricyclic ring system. The benzopyrone fragments are planar. The dihedral angles between the benzopyrone fragment and the phenyl ring being 55.38(6)° for (I) and 44.75(15)° /44.64(15)° for the respective independent molecules of (II) are within the range of values observed for similar structures.     

Characterization of α and γ polymorphs of glycine crystallized from water‐ammonia solution

Crystallization of metastable α and stable γ polymorphs of glycine was carried out from aqueous solution in the presence of ammonia. Pure aqueous solution and solution with lower concentration of ammonia yield α nucleation and solution with a critical concentration of ammonia yield γ nucleation. Variation in the solubility of glycine in double distilled water and pH of the resulting solution due to the ammonia incorporation was studied in a range of temperatures. The induction period for the α and γ nucleation in the solution was determined and its variation due to the ammonia incorporation was also studied. Single crystals of both the polymorphs were grown by slow evaporation method. Effect of ammonia concentration and the resultant pH of the solution on the nucleation, growth and morphology of the grown polymorphs were investigated. The unidirectional growth of the γ polymorph along the polar axis was revealed. X‐ray powder diffraction method was employed to distinguish both the polymorphs structurally. Their thermal stability above room temperature was studied by differential scanning calorimetry which revealed that the as‐grown γ polymorph transforms to α at 179.6 °C while the as‐grown α retains its phase until melting. The optical transmittance of the grown γ polymorph was studied in the UV‐Vis‐Near IR region. The second harmonic generation (SHG) efficiency of the grown γ polymorph was studied with a Nd:YAG laser source and is about 6.8% higher than that of the inorganic standard KDP. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

1:1 Crystal Complexes of 2',6'‐Dimethoxyflavone with 3‐Bromo and 3‐Chloro‐2,6‐dimethoxybenzoic Acid

The structures of two solid inclusion compounds with the 2',6'‐dimethoxyflavone host molecule, 1, were investigated by single‐crystal X‐ray analysis. Both compounds, 1�3‐bromo‐2,6‐dimethoxybenzoic acid (1:1) and 1�3‐chloro‐2,6‐dimethoxybenzoic acid (1:1) crystallize in the centrosymmetric group P‐1. The complexation involves an intermolecular hydrogen bond between the carbonyl group of the flavone and the acidic hydrogen of the acid.     

Odd‐Even Effects in Homologous Series of 4‐Cyano‐4'‐Alkylbiphenyls(nCB): Role of Anisotropic Pair Potential

A quantum mechanical analysis has been carried out to determine the association energy of five homologous of 4‐Cyano‐4'‐Alkylbiphenyls series with alkyl group: propyl (3CB) ; butyl (4CB) ; pentyl (5CB) ; hexyl (6CB) ; hepty (7CB) using Rayleigh‐Schrodinger perturbation method for different nearest neighbour configurations of interacting pairs. The net atomic charges and dipoles have been computed using the CNDO/2 method. The complete association energy with all its components has been reported. An attempt has been made to explain the odd‐even effects at the molecular level on the basis of these results.     

Syntheses and crystal structures of two polymorphs of three‐dimensional silver (I) 5‐(3‐aminophenyl)tetrazolates

Two polymorphs of silver 5‐(3‐aminophenyl)tetrazolates – α‐ and β‐Ag(amphttz) have been obtained by the reaction of amphttzH with AgNO₃ in presence of ammonia either in ambient condition or under the hydrothermal condition, respectively (amphttzH = 5‐(3‐aminophenyl)tetrazole). Both of the two phases of Ag(amphttz) were characterized by elemental analyses, IR spectra and single‐crystal X‐ray diffraction. X‐ray analysis shows α‐, β‐phases crystallize in P ‐1 with a = 8.551 (2) Å, b = 8.720(2) Å, c = 11.173(2) Å, α = 98.15(3)°, β = 90.95(3)°, γ = 95.45(3)° and C 2/c with a = 13.542(3) Å, b = 10.135(2) Å, c = 12.610(3) Å, β = 113.58(3)°, respectively. The two polymorphs exhibit different 3D structures. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure of 4'‐O‐methylalpinumisoflavone at 90K

4′‐O‐Methylalpinumisoflavone crystals which hitherto had been difficult to crystallize for X‐ray diffraction analyses have been obtained from a demethylated product of O, O‐dimethylalpinumisoflavone. The structural and conformational features of the crystal measured at 90 K are reported and compared with previously reported work of O,O‐dimethylalpinumisoflavone and 5‐O‐methyl‐4′‐O‐(3‐methyl‐but‐2‐en‐1‐yl) alpinumisoflavone. Each of these compounds is characterized by a six membered ring that is further fused to a benzopyrone isoflavone moiety resulting in a tricyclic ring system. This six membered ring shows a half‐chair conformation in all the molecules studied, with the ring in the title compound showing the least Cremer‐Pople puckering amplitude Q and shorter inter and intramolecular contacts. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Structural studies of crystalline oligosaccharides VI: Crystal structure and conformation of benzyl‐4,6‐O‐benzylidene‐3‐O‐benzoyl‐β‐D‐galactoside

Monsaccharides are the building blocks of polysaccharides and hence are the simplest sugar molecules to study the conformation and molecular structures of sugars. Benzyl‐4,6‐O‐benzylidene‐3‐O‐benzoyl‐β‐D‐galactoside is a key intermediate in the synthesis of polysaccharides. Crystal structural investigation of the title compound was undertaken to establish their chemical structure as well as to study their solid state conformation. Crystals of the title compound, obtained from water/methanol, are orthorhombic, space group P2₁2₁2₁, with cell dimensions a=11.290 (4), b=9.941 (1), c= 21.442(2)Å, V= 2406ų, Z=4, D_obs= 1.42 gm/cm³, D_calc=1.423 g/cm³, 2886 reflections were collected on a CAD‐4 diffractometer. The structure was solved by direct methods and refined to a final reliability index of 4.7%. The galactoside sugar has the chair conformation with C2' and C5' deviating from the mean plane of the other atoms of the sugar. The 4,6‐O‐benzylidene ring also has a chair conformation with the benzoyl group proximal to O6'. The crystal structure is stabilized by O‐H…O hydrogen bonds involving O2' as donor and three C‐H…O hydrogen bond interactions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal Structure of Spiro[2‐benzoyl‐cyclohexyl‐4,5‐diphenylpyrrolidine‐3,3'‐chroman‐4‐one]

3‐Phenyl‐chroman‐4‐one is the basic unit of isoflavonoids which are found in the plants of the sub‐family papilionoidae of Leguminosae. They are known to possess antifungal and antibacterial properties. Crystal data of the title compound : Monoclinic, space group P2₁/c, a = 14.021(3), b = 18.682(4), c = 11.362(2) Å, β = 95.75(3)°, R = 0.066. The two phenyl rings directly attached to the pyrrolidine ring are nearly perpendicular to it. The dihydropyrone moiety adopts a half‐chair conformation while the cyclohexane ring attached to the pyrrolidine ring adopts a chair conformation. The best plane passing through the chroman‐4‐one moiety makes a dihedral angle of 82.2(3)° with the pyrrolidine ring. The molecule is stabilized by one intra‐ and two intermolecular C‐H...O hydrogen bonds.     

Characterization of in‐plane structures of vapor deposited thin‐films of distyryl‐oligothiophenes by grazing incidence x‐ray diffractometry

The in‐plane structures of vapor deposited ultrathin films of distyryl‐oligothiophenes (DS‐2T) on SiO₂ substrate were characterized by grazing incidence x‐ray diffractometry (GIXD). Two polymorphs, low‐temperature and high‐temperature phases, were identified, and the two dimensional unit cell parameters were determined for each polymorph. The polymorphism depends on substrate temperature and film thickness. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Isolation and characterization of a new polymorph of D‐sorbitol

A new polymorph of D‐sorbitol (named as F form) was discovered in this paper. A reliable isolation method for this new polymorph was developed. Three other known polymorphs of D‐sorbitol were also prepared for comparative purpose. The new F form was analyzed and characterized by using PXRD, DSC, Raman and FTIR spectroscopy. By comparing with current polymorphs' data, it was proved that F form is a new form that was not reported in any literatures. From PXRD data, it was confirmed that the crystallinity of the new form is very high. From DSC data, it was found that the new form is less stable than any known anhydrous forms. It was also found by transformation experiments that the new F form can transform into alpha form in methanol solution through a solution mediated transformation mechanism. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis,characterization and crystal structure of a 2D Cd(II) complex with a 4,4'‐diazenediyldiphthalic acid ligand

An exploration of the cadmium‐L system under hydrothermal condition, has led to the isolation of a novel framework {[Cd(L)_0.5(H₂O)₃]}_n ( 1 ) (H₄L = 4,4'‐diazenediyldiphthalic acid). Single‐crystal X‐ray analysis reveals that it crystallizes in the triclinic space group P‐1. a = 5.746(3) Å, b =6.526(4) Å, c = 14.701(8) Å, α=92.348(8), β = 99.622(6), γ=106.877(7)°. The Cd^II ions are linked into an extended 2‐D rectangle‐like structure via L ligands, which exhibits an attractive three‐connected honeycomb topological network. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure of 2‐(2'‐hydroxyphenyl)‐6‐tributylstannyl‐4‐(3H )‐quinazolinone and 2‐(2'‐hydroxyphenyl)‐6‐iodo‐4‐(3H)‐quinazolinone

The structures of the title compounds C₂₆H₃₇N₂O₂Sn ( I ) and C₁₄H₉IN₂O₂ ( II ) were determined by single‐crystal X‐ray diffraction technique. Compound I crystallizes in the triclinic space group P1 with a = 9.560(3) Å, b = 16.899(6) Å, c = 17.872(5) Å, α = 65.957(7)°, β = 83.603(5)°, γ ( = 75.242(5)°, V = 2549.8(13) ų, Z = 4, and D =1.374 g/cm³. The compound consists of a quinazolinone ring with phenol and tributylstannyl moieties. Compound II crystallizes in the monoclinic space group P2₁/c with a = 7.6454(12) Å, b = 5.9270(9) Å, c = 27.975(4) Å; α = 90°, β = 95.081(3)°, γ = 90°, V = 1262.7(3) ų, Z = 4, and D = 1.915 g/cm³. The compound consists of a quinazolinone ring with phenol and iodine substituents. For both I and II , the short intramolecular O–H…N and two long intermolecular N–H…O hydrogen bonds are highly effective in holding the molecular system in a stable state. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystallization of β‐glycine by spray drying

Glycine crystallization during spray drying has been investigated on a laboratory scale. In order to obtain different polymorphs the experiments have been performed at different hot air temperatures, concentrations, different flow of the solution and spraying air. The obtained crystals were analyzed by means of X‐ray powder diffractometry, differential scanning calorimetry and the Fourier transform infrared spectrometry. Crystallization mostly resulted with a mixture of α‐ and β‐glycine with a small amount of γ‐glycine. The glycine polymorphism is affected by the drying air temperature, concentration and the flow of the solution, as well as the spraying air flow. Decrease of the drying air temperature and increase of the solution flow rate causes the increase of the quantity of β‐glycine. At room conditions, β‐glycine spontaneously transforms into thermodynamically more stable α‐glycine. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis of ZnSnN2 crystals via a high‐pressure metathesis reaction

The synthesis of crystals of a zinc‐ and tin‐based earth‐abundant element nitride (ZnSnN₂) semiconductor was successfully achieved via a metathesis reaction under high pressure. Pressures exceeding 5.5 GPa were required to obtain single‐phase crystals. The material's bandgap was determined to be 1.4 eV, which is ideal for photovoltaic absorbers and visible light‐active photocatalysts. The decomposition temperature of the material was estimated to be approximately 350‒400 °C at atmospheric pressure. Finally, the chemical stability of the material against alkali and acid solutions was sufficient for photovoltaic and photocatalytic applications.     

Phase‐controlled crystallization of amorphous calcium carbonate in ethanol‐water binary solvents

The evolution of amorphous calcium carbonate (ACC) into crystals in ethanol/water binary solvents under ambient temperature was investigated, and it was found to depend on the volume ratio of ethanol to water (R). Calcite remained dominant when the amount of water was high (R = 1/3). A slight change in the amount of ethanol (R = 3/1) could lead to a dramatic change in the polymorph from calcite to aragonite. However, when poly (allylamine hydrochloride) (PAH) was added at R = 3/1, almost pure vaterite could be obtained, which has a specific morphological variation (from hollow microspheres to cloud‐like). This study provides an alternative polymorphic route for the CaCO₃ mineral by using the evolution of ACC in different solvent environments, which provides some useful clues for understanding the importance of kinetic control of the morphologies and polymorphs of a wide range of inorganic materials. In addition, this simple mild phase‐controlled synthetic method could be scaled up as a green chemistry route for the industrial production of different polymorphs of CaCO₃.     

Crystal structure and conformational analyses of a synthetic tetrapeptide t‐Boc‐L‐Val‐Aib‐Gly‐L‐Leu‐OMe

Crystal structure of a terminally blocked synthetic peptide, t‐Boc‐L‐Val‐Aib‐Gly‐L‐Leu‐OMe has been investigated. Two different conformers of peptide with one co‐crystallized water molecule, coexist in the crystal structure, in C2 space group. Both the conformers are stabilized by two intramolecular 1← 4 hydrogen bonds, between (Boc) C=O … HN (Gly) and (Val) C=O … HN (Leu), forming consecutive type II‐I' β‐turns. In the crystal, water interlinks peptide molecules, making a triangular bridge of pyramidal type. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth of boron nitride films on w‐AlN (0001), 4° off‐cut 4H‐SiC (0001), W (110) and Cr (110) substrates by Chemical Vapor Deposition

Boron Nitride is a promising group 13–group 15 compound material that exhibits various interesting properties like wide band gap, chemical stability, attractive mechanical properties and other. The growth behavior of this material has not been investigated in sufficient details to tailor properties of the resulting films. In this work we present the results on the growth of turbostratic boron nitride (t‐BN) thin films at a relatively high growth rate of 3 μm/h with the aim to investigate the potential use of boron trichloride in combination with ammonia as precursors for growth. Deposition experiments were conducted in a vertical cold wall high temperature chemical vapor deposition reactor in the temperature range 1000°C–1700°C depending on the substrate used. Templates of w‐AlN (0001), 4° off‐cut 4H‐SiC (0001), Cr (110) and W (110) were employed as substrates for the BN growth. As‐grown BN layers were characterized by Scanning Electron Microscopy, X‐Ray Diffraction, Electron Diffraction and Raman Spectroscopy. The results indicate that temperature and N/B ratio have a great influence on the crystallinity of the deposited films. For AlN and SiC substrates, a temperature of 1600°C and N/B ratio in range between 3 and 7.5 were identified as the best parameters for the growth of a 2 μm thick t‐BN layer with a spacing between basal planes of about 3.36 Å compare to the 3.33 Å spacing between basal planes of hexagonal or rhombohedral BN (h‐BN or r‐BN). For Cr and W substrates which have a lower mismatch with h‐BN (1 and 8.8 %), layers of t‐BN were deposited at much lower temperature (1000°C–1150°C) with a spacing between basal planes of 3.5 Å and morphology similar to that observed on SiC substrates. We obtained t‐BN layers with in plane strong disorder but out of plane orientation (c‐axis normal to the surface).     

XRD,thermal, FTIR and SEM studies on gel grown γ‐glycine crystals

Glycine is the smallest among amino acids. The polymorphs, α‐ and γ‐forms of glycine were crystallized in silica gel by reduction of solubility method. The grown crystals were characterized by single crystal X‐ray diffraction studies and density determination. Fourier transform infrared spectroscopic studies and thermogravimetric analysis of γ‐glycine were also conducted. Morphological and scanning electron microscopic (SEM) studies were also made and compared with the crystal packing. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal Structure of Dimeric Cu(II) Complex {μ,μ'‐acetato O,O bis [N‐salicylidene‐2‐amino‐pyridine‐methanolato N,N,O]} : perchlorate

The crystal structure of the title complex has been solved using X‐ray diffraction data.The compound crystallizes from aqueous ethanol solvent in the triclinic system, space group P‐1, with unit cell parameters: a = 8.9532(1), b = 12.7423(3), c = 14.9012(3) Å, α = 73.767(1), β = 75.322(1), γ = 77.496(1)°, Z = 2, V = 1559.4(5) ų. The trial structure was determined by automated Patterson methods and subsequent difference Fourier techniques using DIRDIF98 and refined to a final R‐factor of 0.064. The copper ion Cu1 adopts a (4+1) square‐pyramidal geometry defined by the tridentate N‐salicylidimine dianions and the neutral monodentate pyridine ligand in the basal plane. The apical position is occupied by a solvent methanol molecule at a distance of 2.341(4) Å. The copper Cu2 adopts a square‐planar geometry.