A tetranuclear copper (II) complex with pyrazole-3,5-dicarboxylate ligands: synthesis, characterization and electrochemical properties

2016 ◽  
Vol 71 (4) ◽  
pp. 305-310 ◽  
Author(s):  
Selçuk Demir ◽  
Hamide Merve Çepni ◽  
Małgorzata Hołyńska ◽  
Muammer Kavanoz
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Metal Oxidation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complex Anions

AbstractA tetranuclear copper (II) complex with pyrazole-3,5-dicarboxylate ligands (pdc3−), [Me2NH2]4[Cu4(pdc)4], was synthesized using solvothermal and metal oxidation routes and characterized by elemental analysis, infrared, thermogravimetry/differential thermal analysis, and room-temperature magnetic measurements. The structure of the complex was determined by single-crystal X-ray diffraction. It comprises dimethylammonium cations and complex anions containing four Cu2+ cations. The crystal structure is stabilized by N–H···O hydrogen bonds. In addition, the electrochemical behavior was studied.

X-ray Diffraction Studies of Solid Solutions of Pentaglycerine-Neopentylglycol

1988 ◽  
Vol 32 ◽  
pp. 609-616 ◽  
Author(s):  
D. Chandra ◽  
C. S. Barrett ◽  
D. K. Benson
Keyword(s):  
Crystal Structure ◽  
Energy Storage ◽  
Hydrogen Bonds ◽  
Solid Solutions ◽  
Room Temperature ◽  
Energy Storage Materials ◽  
Anisotropic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Structure

AbstractAn array of molecules that is anisotropic in the extreme has been discovered in certain thermal-energy storage materials and is reported here: neopentylglycol (NPG) and NPG-rich solid solutions with pentaglycerine (PG) have a crystal structure, stable at room temperature, that consists of bimolecular chains of molecules that are all unidirectionally aligned throughout a crystal. There are hydrogen bonds between every molecule in one chain and its neighbors in that chain, but none between molecules of one chain and any molecules of the neighboring parallel chains. Thus there are strong intermolecular bonds along each chain and only weaker bonds between the chains. The structure has been determined by using modern single crystal techniques with 529 independent reflections from a crystal of NPG (C5H12O2). The structure is monoclinic with space group P21/c - C2h5. This anisotropic structure transforms to a cubic structure at higher temperatures.

scholarly journals Thermal Annealing and Phase Transformation of Serpentine-Like Garnierite

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 188
Author(s):  
Arun Kumar ◽  
Michele Cassetta ◽  
Marco Giarola ◽  
Marco Zanatta ◽  
Monique Le Guen ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Raman Spectroscopy ◽  
Phase Transformation ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Thermally Induced ◽  
X Ray ◽  
Micro Raman Spectroscopy

This study is focused on the vibrational and microstructural aspects of the thermally induced transformation of serpentine-like garnierite into quartz, forsterite, and enstatite occurring at about 620 °C. Powder specimens of garnierite were annealed in static air between room temperature and 1000 °C. The kinetic of the transformation was investigated by means of thermogravimetric and differential thermal analysis, and the final product was extensively characterized via micro-Raman spectroscopy and X-ray diffraction. Our study shows that serpentine-like garnierite consists of a mixture of different mineral species. Furthermore, these garnierites and their composition can provide details based on the mineralogy and the crystalline phases resulting from the thermal treatment.

Crystal growth and structure analysis of Sm2−xCexCuO4

2000 ◽  
Vol 15 (9) ◽  
pp. 1905-1910 ◽  
Author(s):  
H. Takeda ◽  
M. Okuno ◽  
M. Ohgaki ◽  
K. Yamashita ◽  
T. Matsumoto
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Phase Diagram ◽  
Differential Thermal Analysis ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
Zone Method ◽  
Floating Zone Method ◽  
X Ray ◽  
Quench Method

The phase diagram of the Sm2O3–CuO system was investigated by the combination of the differential thermal analysis and the quench method. The results showed that Sm2CuO4 incongruently melts at about 1220 °C, and that the solid Sm2CuO4 exists in equilibrium with the liquid consisting of 81–95 mol% CuO in the range of 1060–1220 °C. On the basis of the phase diagram, Sm2−xCexCuO4 single crystals were grown by the traveling solvent floating zone method. The crystal structure [space group I4/mmm, a = 3.917(1), c 4 11.899(2) Å] has been refined using single-crystal x-ray diffraction data with a precision corresponding to an R index of 0.02.

Structures and phase transitions of (BrCH2CH2NH3)2CdBr4 and (BrCH2CH2CH2NH3)2CdBr4 as investigated by 81Br NQR, DTA, and single-crystal X-ray diffraction

2020 ◽  
Vol 75 (3) ◽  
pp. 295-302
Author(s):  
Hideta Ishihara ◽  
Asuka Koga ◽  
Koh-ichi Suzuki ◽  
Hiromitsu Terao
Keyword(s):  
Thermal Analysis ◽  
Hydrogen Bonding ◽  
Differential Thermal Analysis ◽  
Phase Transitions ◽  
Hydrogen Bonds ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
X Ray ◽  
81Br Nqr ◽  
Successive Phase

AbstractThe crystal structures of (BrCH2CH2NH3)2CdBr4 (1) and (BrCH2CH2CH2NH3)2CdBr4 (2) have been determined at T = 113 K: orthorhombic, Pbcn, a = 843.8(4), b = 775.4(4), c = 2339.6(11) pm, Z = 4 for 1; orthorhombic, Pbcn, a = 858.7(3), b = 783.6(2), c = 2519.4(7) pm, Z = 4 for 2. Both crystals are isomorphic, showing distinctive layered perovskite-related structures, in which the cations orient their aliphatic parts toward each other in their cation layers and connect to the infinite anion layers with their ammonium parts through N–H · · · Br hydrogen bonds. 81Br NQR and differential thermal analysis measurements for both compounds revealed the existence of successive phase transitions as seen in n-(CH3CH2CH2NH3)2CdBr4 (3). These phase transitions appear to be induced by the activated motions of the cations. The changes in the hydrogen bonding schemes resulting from the motions of the cations lead to the different phases of the respective crystals.

scholarly journals Fabrication of Aligned Side-by-Side TiO2/SnO2Nanofibers via Dual-Opposite-Spinneret Electrospinning

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Fu Xu ◽  
Luming Li ◽  
Xiaojie Cui
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermal Degradation ◽  
Anatase Phase ◽  
Electrospun Fibers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bicomponent Fibers ◽  
Photocatalytic Materials

Well-aligned and uniform side-by-side bicomponent fibers have been produced via dual-opposite-spinneret electrospinning. Side-by-side TiO2/SnO2nanofibers were obtained after calcining as-spun fibers. The thermal degradation of the electrospun fibers was evaluated using combined thermogravimetry and differential thermal analysis (TG-DTA), and the crystal structure of calcined nanofibers was investigated by X-ray diffraction (XRD). The fabricated TiO2/SnO2nanofibers expose both TiO2mainly consisting of anatase phase and rutile-type SnO2to the surface, which is appropriate for photocatalytic materials.

Structural, kinetic and thermodynamic aspects of the conformational dimorphism of diethyl 3,6-dibromo-2,5-dihydroxyterephthalate

1996 ◽  
Vol 52 (4) ◽  
pp. 697-706 ◽  
Author(s):  
C. Näther ◽  
N. Nagel ◽  
H. Bock ◽  
W. Seitz ◽  
Z. Havlas
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Room Temperature ◽  
Molecular Conformation ◽  
Local Energy ◽  
X Ray Diffraction ◽  
Ethanolic Solution ◽  
Crystal Forms ◽  
X Ray ◽  
Ethanol Solvate

The crystal structures of the title compound and of its ethanol solvate have been determined by X-ray diffraction. The compound crystallizes in two different crystal forms (I: P21/n, high-temperature stable modification, II: P21/c, room-temperature stable modification), which differ in molecular conformation and hydrogen bonding. Ab initio calculations show that both observed conformations correspond to local energy minima and predict the conformation in polymorph (II) to be energetically more favourable. Packing energy calculations confirm that form (II) should be more stable than form (I). Crystals of both modifications and a solvate, containing 2 equiv, of ethanol, can be obtained by slow crystallization from ethanolic solution. Modification (II) transforms to (I) at 391 K, as shown by optical microscopy, powder diffraction and differential thermal analysis (DTA), whereas (I) melts at 429 K without previous transformation.

scholarly journals A New Decavanadate with Organic Cation: Synthesis, Crystal Structure, and Hirshfeld Surface Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Rawia Nasri ◽  
Regaya Ksiksi ◽  
Mohsen Graia ◽  
Mohamed Faouzi Zid
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Organic Cation ◽  
Three Dimensional ◽  
Hirshfeld Surface ◽  
Van Der Waals Interactions ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray

A new 2,6-bis aminomethyl piperidine decavanadate hydrate, (C7N3H20)2V10O28.4.21H2O, was synthesized by slow evaporation of a solution at room temperature. The molecular structure was investigated by single-crystal X-ray diffraction. In the crystal structure, the layers of decavanadate groups, organic cations, and water molecules are arranged parallel to the (010) plane. Also, the prepared compound has been analysed by FTIR spectroscopy and scanning electron microscopy (SEM). The crystal structure of the title compound is stabilized by hydrogen bonds and van der Waals interactions. The cohesion of the structure is ensured by O-H…O and N-H…O hydrogen bonds. The three-dimensional Hirshfeld surface (3D-HS) and the relative two-dimensional fingerprint plots (2D-FPs) of (C7N3H20)2V10O28.4.21H2O compound revealed that the structure is dominated by O…H/H…O (70.8%) and H…H (18.5%) contacts.

Crystal Structure of Pyridinium Periodate

1998 ◽  
Vol 53 (11) ◽  
pp. 1323-1325 ◽  
Author(s):  
Grzegorz Dutkiewicz ◽  
Zdzisław Pająk
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Pyridinium Cations

The crystal structure of the room-temperature ferroelectric phase of pyridinium periodate [C6H5NH]+[IO4]- has been determined by X-ray diffraction as orthorhombic, space group Cmc2i with a = 8.347(2), b = 7.270(2), c = 12.732(3) Å and Z = 4. It was refined to R1 =0.0281 wR2 = 0.0762 for 389 absorption-corrected reflections. The structure comprises isolated IO4 tetrahedra linked together by disordered pyridinium cations involved in a network of bifurcated hydrogen bonds. The average I-O distance is found to be 1.75(1) Å.

scholarly journals Thermal Annealing and Phase Transformation of Serpentine-like Garnierite

2021 ◽  
Author(s):  
Arun Kumar ◽  
Michele Cassetta ◽  
Marco Giarola ◽  
Marco Zanatta ◽  
Monique Le Guen ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Phase Transformation ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Thermal Annealing ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Thermally Induced ◽  
X Ray ◽  
Microraman Spectroscopy

This study deals with vibrational and crystallographic aspects of the thermally induced transformation of serpentine-like garnierite into quartz, forsterite, and enstatite occurring at about 620 °C. Powder specimens of garnierite have been annealed in static air between room temperature and 1000 °C. The resulting products from the transformations detected based on thermogravimetric and differential thermal analysis, have been extensively characterized via microRaman spectroscopy, and X-ray diffraction. Our study shows that serpentine-like garnierite consists of a mixture of different mineral species. Furthermore, these garnierites and their composition can provide details based on the mineralogy and the crystalline phases resulting from the thermal treatment.

PENINGKATAN LAJU DISOLUSI ACYCLOVIR DENGAN METODE SISTEM DISPERSI PADAT MENGGUNAKAN POLOXAMER 188

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Fourier Transform Infrared ◽  
X Ray Diffraction ◽  
Poloxamer 188 ◽  
X Ray ◽  
Scanning Electron

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.

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