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Slow Evaporation (slow + evaporation)
Selected AbstractsHabit modification and improvement in properties of potassium hydrogen phthalate (KAP) crystals doped with metal ionsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2006S. K. Geetha Abstract Potassium hydrogen phthalate (KAP) single crystals were grown by slow evaporation and slow cooling techniques. The growth procedure like temperature cooling rate, evaporation rate, solution pH, concentration of the solute, supersaturation ratio etc., has been varied to have optically transparent crystals. Efforts were made to dope the KAP crystals with rubidium, sodium and lithium ions. The dopant concentration has been varied from 0.01 to 10 mole percent. Good quality single crystals were grown with different concentrations of dopants in the mother phase. Depending on the concentration of the dopants and the solution pH value, there is modification of habit. Rubidium ions very much improve the growth on the prismatic faces. The transparency of the crystals is improved with rubidium and sodium doping. The role of the dopants on the non-linear optical performance of KAP indicates better efficiency for doped crystals. The grown crystals were characterized with XRD, FT-IR, chemical etching, Vickers microhardness and SHG measurements. The influence of the dopants on the optical, chemical, structural, mechanical and other properties of the KAP crystals was analysed. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim [source] Synthesis, structural and thermal studies of tetrathioureacopper(I) chloride crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2005M. Dhandapani Abstract Tetrathioureacopper(I) chloride, hereafter abbreviated as TCC, was synthesised and single crystals were obtained from saturated aqueous solution by slow evaporation (solution growth) method at room temperature. The crystals obtained are bright, colourless and transparent having well defined external faces. The grown crystals were characterized through elemental analysis, single crystal X-ray diffraction study, thermal analysis, electron spin resonance spectroscopy and Fourier Transform infrared spectroscopy. The elemental analysis confirms the stoichiometry of the compound. The single crystal diffraction studies indicate that TCC crystallises in the tetragonal lattice and the unit cell parameters are a = b = 13.4082 Å, c = 13.8074 Å, V = 2482.29 Å3, , = , = , = 90°. Space group and the number of molecules per unit cell (Z) are found to be P41212 and 8 respectively. The TG curve of the sample shows a prolonged decomposition from 210 to 628.3 °C, from which the decomposition pattern has been formulated. The endothermic peaks in the DTA curve indicate melting and decomposition of the compound at 165.2 and 633.8 °C respectively. An exothermic peak in high temperature DSC indicates a phase transition in the compound at 274.8 °C. Thermal anomalies observed in the low temperature DSC at ,163.3, ,152.0, ,141.5, ,108.3, 1.0 and 12.1 °C in the heating run and ,157.1 and ,153.9 °C in the cooling run reveal first order phase transitions in the crystal. The peaks observed at ,146.2 °C in both the heating and cooling runs suggest occurrence of a second order phase transition in this compound. The IR spectroscopic data were used to assign the characteristic vibrational frequencies of various groups present in the compound. The ESR study confirms that the copper is in the +1 oxidation state in the complex. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Organic Electro-optic Single- Crystalline Thin Films Grown Directly on Modified Amorphous Substrates,ADVANCED MATERIALS, Issue 3 2008O-P. Kwon High quality organic electro-optic single crystalline thin films are produced on amorphous C,N-modified glass substrates (see figure), which is a mimic surface of a crystal, by slow evaporation and capillary methods. The films have a suitable size (shaped as rectangular plates with side lengths in the range of 5,10 mm and regular thicknesses in the range of 1,40 ,m) for the fabrication of photonic devices. [source] Synthesis and preliminary characterization of sulfamethazine-theophylline co-crystalJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2010Jie Lu Abstract Co-crystals containing active pharmaceutical ingredients (APIs) represent a new type of pharmaceutical materials. In this work, sulfamethazine (STH) and theophylline (TP) were employed as the co-crystal formers. Neat cogrinding, solvent-drop cogrinding and slow evaporation were applied to synthesize the sulfamethazine,theophylline co-crystal (hereafter STH,TP co-crystal). The co-crystalline phase was characterized by DSC, TGA, Raman, PXRD, and dynamic vapor sorption (DVS) techniques. The STH,TP co-crystal structure was determined from single crystal X-ray diffraction data. The results show that, the STH,TP co-crystal, obtained in a 2:1 molar ratio of sulfamethazine and theophylline only by slow evaporation, possesses unique thermal, spectroscopic, and X-ray diffraction properties. Besides, in the STH,TP co-crystal, the sulfamethazine molecules form a dimer through the intermolecular hydrogen bonding (O ··· H N), and two intermolecular hydrogen bonds (O ··· H N and N ··· H N) keep the theophylline attached the dimer. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:4042,4047, 2010 [source] Regioregular Poly[3-(4-alkoxyphenyl)thiophene]s: Evidence for a Two-Step Aggregation ProcessMACROMOLECULAR RAPID COMMUNICATIONS, Issue 14 2006Guy Koeckelberghs Abstract Summary: A chiral, regioregular poly[3-(4-alkoxyphenyl)thiophene] has been prepared and studied. Films prepared by fast evaporation of the solvent, consist of random-coils, while films prepared by slow evaporation are composed of chirally aggregated, coplanar strands. Heat treatment transforms the random-coils into aggregated films via an intermediate state, which was characterized as chiral, coplanar, unaggregated polymer strands. Overview of the possible aggregation processes. [source] Halogeno(triazolyl)zinc complexes as molecular building blocks for metal,organic frameworksACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009Jörg Lincke The isomorphous title complexes, dichlorido[4-(3,5-dimethyl-4H -1,2,4-triazol-4-yl)benzoic acid-,N1]zinc(II) dihydrate, [ZnCl2(C11H11N3O2)2]·2H2O, and dibromido[4-(3,5-dimethyl-4H -1,2,4-triazol-4-yl)benzoic acid-,N1]zinc(II) dihydrate, [ZnBr2(C11H11N3O2)2]·2H2O, were synthesized and crystallized by slow evaporation of the solvent from a solution of the ligand and either zinc chloride or zinc bromide, respectively, in water/ethanol. The ZnII ions occupy twofold axes in the noncentrosymmetric orthorhombic space group Fdd2. The metal ion is approximately tetrahedrally coordinated by two monodentate triazole groups of the ligands and additionally by two halide ions. The water molecules incorporate the complexes into a three-dimensional framework made up by hydrogen bonds. Furthermore, each complex possesses two hydrogen-bond-donor sites represented by the carboxy groups and two acceptor sites at the noncoordinating N atoms of the triazoles. [source] Two new polymorphs of diphenyl(4-pyridyl)methyl methacrylateACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2004Gerrit Gobius du Sart The title compound (D4PyMA), C22H19NO2, exhibits polymorphism after crystallization by slow evaporation from a binary mixture of chloroform and hexane. Long needle-like crystals have an orthorhombic structure (space group Fdd2), with one molecule in the asymmetric unit, while small tablet-like crystals exhibit a monoclinic crystal structure (space group P21/n), in which two independent but chemically identical molecules comprise the asymmetric unit. The bond lengths and angles are normal, while the torsion angles around the ,C,O, bond linking the diphenyl(4-pyridyl)methyl and methacrylate groups show the flexibility of the molecule by way of packing effects. The two polymorphs both contain weak C,H,, and C,H,O/N contacts but have different conformations. [source] | |||||||||||||