Synthesis, crystallographic characterization, and thermal analyses of five 5-methyl-1H-tetrazole salts

One-pot synthesis, crystallographic characterization, evaluation as in vitro antibacterial and cytotoxic agents of two mercury(II) complexes containing pyridine dicarboxylic acid derivatives

Chemical preparation, thermal behavior, kinetic and IR studies are given for the cyclotriphosphate Ca3(P3O9)2•10H2O. Ca3(P3O9)2•10H2O is monoclinic P21/n with the following unit-cell dimensions: a = 9.332(7)A, b = 18.13(1)A, c = 7.841(5), β = 106.69(5)° and Z = 2. Ca3(P3O9)2•10H2O has never been studied except for its crystallographic characterization. The thermal behavior of Ca3(P3O9)2.10H2O has been studied and interpreted by comparison with IR absorption spectrometry, X-ray diffraction experiments, chemical analyses, thermal analyses (TGA-DTA) and differential scanning calorimetry (DSC). Ca3(P3O9)2•10H2O is stable, in the conditions of temperature and pressure of our laboratory, until 80°C. It is impossible to dehydrate Ca3(P3O9)2•10H2O without breaking its rings P3O93- and leading to amorphous compounds in X-ray diffraction and IR absorption spectrometry. The final product of the dehydration and calcination of Ca3(P3O9)2•10H2O, under atmospheric pressure is its long chain polyphosphate form β, β[Ca(PO3)2]8. β[Ca(PO3)2]8 is stable until its melting point at 1097°C. On the other hand, β[Ca(PO3)2]8is prepared by dry way. β[Ca(PO3)2]8 has many applications in industry such as humidity sensor and corrosion inhibitor. Also, quantum chemical calculations have been performed for the P3O9 rings.

Electrolytic oxidation of 3-amino-1,2,4-triazole with ammonium nitrate as electrolyte yielded single crystals of 3-amino-1,2,4-triazole nitrate salt, which was previously reported but lacked structural and thermal data. In this work, we employ thermal and other analyses to better characterize the aforementioned salt. The salt released significantly more heat (2359 J/g) than the raw materials (909, and 1171 J/g, respectively) or their mixture (2112 J/g) in SC-DSC measurements. TG-DTA measurements revealed that a higher onset temperature of weight loss for the salt, although complete gasification was unobserved. Crystallographic data enabled calculations of the detonation velocity, which ranged from 7834 to 8101 m/s.

Chemical preparation, crystallographic characterization, thermal behavior and IR studies of two new cyclotriphosphates SrKP3O9·3H2O and SrKP3O9

The complete phase diagram of the plastic crystals Pentaerythritol (PE) and Pentaglycerin (PG) has been established by means of thermal analysis and X-ray diffraction. The phase diagram is characterized by a wide crystal-plastic equilibrium and a very narrow plastic-liquid equilibrium. The crystallographic characterization allows us to conclude the total miscibility in both solid phases. Moreover, the different evolutions of the crystalline parameters of the tetragonal lattice with the concentration at 293 K are interpreted by the anisotropy between the bonds in the (001) layers (strong intermolecular hydroxyl hydrogen bond) and the bonds of the interlayers (Van der Waals forces).

Combination of three techniques of thermal analysis (hot stage polarising microscope, DSC, Guinier-Lenne) enabled the determination of the polymorphic behaviour of tetra 1,2,4,5-X benzene (X=Cl, Br). Thermal, calorimetric and crystallographic characterizations have been carried out. This study puts forward an interesting problem: theβ phase (P21/a, stable at room temperature) of the tetra chlorobenzene has similar arrangement to the two solid piases P21/a of tetra bromobenzene. Which one of these two forms is actually isomorphic with tetra chlorobenzene. Eine Kombination dreier thermoanalytischer Methoden (Hot-stage Polarisationsmikroskop, DSC, Guinier-Lenne) ermöglichte die Bestimmung des polymorphen Verhaltens von Tetra-1,2,4,5-X-benzol (X=Cl, Br). Es wurde eine thermische, kalorimetrische und kristallographische Charakterisierung durchgeführt. Diese Untersuchung wirft ein interessantes Problem auf: dieβ-Phase (P21/a, stabil bei RT) von Tetrachlorbenzol besitzt eine ähnliche Konfiguration wie die zwei Festphasen P21/a von Tetrabromobenzol. Welche dieser beiden Formen ist mit Tetrachlorbenzol isomorph? Комбинация трех мето дов термического ана лиза (поляризационная мик роскопия с нагревом, ДСК, Гюнье-Ле нн) позолила установи ть полиморфный характе р 1,2,4,5-тетра-Хбензолов, где X=Сl или Вг. Проведен ы термические, калориметрические и кристаллографическ ие измерения. Проведе нное исследование выявил о интересную проблем у:β-фаза тетрахлорбенз ола (устойчива при ком натной температуре и имеюща я симметрию P2j/a) подобна двум твердот ельным фазам тетрабр омбензола с симметрией Р21/а. Какая из этих двух форм действительно и зоморфна сβ-фазой тетрахлорбензола, тр ебует дальнеших иссл едований.

By utilizing an expedient anion exchange protocol and starting with an improved synthesis of 2‐azido‐1,3‐dimethoxyimidazolium hexafluorophosphate, a series of six metathetical salts, including the energetic nitrate and perchlorate as well as the halides, was prepared. We focused on the crystallographic and thermal characterization of these compounds, representing intrinsically reactive hybrid organic / inorganic salts, and conducted a small comparative study with the related 2‐methyl‐1,3‐dimethoxyimidazolium salts. The latter compounds were expected to thermally disintegrate less sluggishly since the covalent azido‐group as intrinsic blasting initiator is missing. Both 2‐azido‐ and 2‐methylimidazolium nitrate exhibit a very sharp thermal onset of complete disintegration. In contrast, the respective perchlorates display a continuous thermogravimetric weight loss over a broad temperature range. Additionally, X‐ray single crystal structure determinations were performed for eight of the new compounds as well as for two 2‐azido‐1,3‐dimethoxyimidazolium salts with a mixed anion composition. Phase purity was also checked for five of the congeners using powder X‐ray diffraction (Pawley fitting). Notably, in the 2‐azido‐imidazolium cation, the intra‐ring bonds of the N1−C2 type were found to be significantly shorter than N1−C4 type bonds, and a characteristic asymmetry between the two N1−C2−N(azido) bond angles was observed. The experimental cation geometry was reproduced by DFT calculations on selected compounds.

The present paper discusses the thermal analysis of pure and copper doped sodium hexa-titanate (Na2Ti6O13) (NHT). These samples were synthesized by the conventional solid-state reaction method having 4, 8 and 12% doping. The XRD and FE-SEM of the pure and doped samples have been done for crystallographic and morphological characterization, which reveals the single-phase formation of samples and the particle size in the micrometer range and rod-shaped. Thermal analysis (DSC/TGA) of the samples has also been done for the phase transition study.KeywordsSodium Hexa-titanateDSCTGAXRDFE-SEM

This paper presents experiments carried out to assess physicochemical characteristics of oxaliplatin (OXPt) and to determine its compatibility with the polymeric matrices with most relevance in development of topical drug delivery systems (DDS). Thermal analysis (DSC and DTG) associated with molecular, crystallographic and morphologic (optical microscopy) characterizations of the drug alone or associated with such polymeric matrices was conducted. OXPt could be classified as a class III drug according to BCS, i.e., is highly water soluble but low permeable. OXPt in solid state showed to be adequate for regular pharmaceutical manufacturing conditions, being stable even when exposed to heating and light. Among tested polymers, only chitosan of medium molecular mass showed to be incompatible with OXPt, with strong evidence of chemical decomposition and physical changes in drug-polymer samples. Low molecular mass chitosan, poloxamer 407 and polylactic-co-glycolic acid (PLGA) may be indicated for the development of innovative topical DDS.

The single-crystal X-ray diffraction structure of the sodium salt of N-(3-(aminosulfonyl)-4-chloro-2-hydroxyphenyl)-N'-(2,3-dichlorophenyl) urea at 173 K is reported. The structure contains 3 mol of water situated in distinct channels in the vicinity of the sodium cation. Powders of this phase undergo isomorphic dehydration, losing 0.5% w/w water between 90 and 15% relative humidity (RH) at 25 °C without changing the powder X-ray pattern. Below 15% RH and above 50 °C, additional dehydration occurs in conjunction with a reversible phase transition. A third semicrystalline dehydrated phase appears after vacuum-drying and at high temperatures and also can be reversibly rehydrated to the original form. Single crystals of the dehydrated phases could not be prepared, so a combination of methods were used to understand the structural changes occurring during the desolvation process, including thermal analysis, vapor sorption measurements, variable-humidity and variable-temperature powder X-ray diffraction, vibrational spectroscopy, and 1H, 13C, 15N, and 23Na magic-angle spinning (MAS) solid-state NMR. The uptake of water vapor into the trihydrate form was investigated by NMR and vibrational spectroscopy using isotopically labeled water. Static 2H and 17O NMR quadrupolar line shape analysis combined with changes in MAS spectra showed exchanged sites on the parent and water molecules. The results indicate that two moles of ion-associated water in the larger tunnel are more labile than a hydrogen-bonded mole of water. Entire water molecules can exchange into the lattice to a small extent, but more efficient hydrogen transfer exchange is observed in the main channel and a smaller perpendicular side channel. The exchanged water deuterons execute rapid three-site jump motions at 273 K.

Structural characterisation of gold nanowire arrays

Thermogravimetric and difference thermal analyses show that the reactions of lithium nitride with the transition metals Cu and Ni under molecular nitrogen to form phases Li2[(Li1‐xMIx)N] take place above 673 K. The maximum weight gains are reached at 926 K and 968 K for M = Cu and Ni, respectively. At higher temperatures, the ternary phases Li2[(Li1‐xMIx)N] decompose, limiting the substitutional level x. In the temperature range of 773 K — 873 K, the successful synthesis of Li2[(Li1‐xNiIx)N] (0 < x ≤ 0.85(1)) single phase products is demonstrated. Maximum substitution obtained for the Cu phases is xmax= 0.43(1). The dependence of the lattice parameters of the hexagonal unit cell on x is almost linear. The magnetic moment of M strongly depends on x. At low x the magnetic moments in phases with M = Ni are presumably enhanced by orbital effects. A decrease of μeff with x to μeff(x = 1) → 0 is explained by delocalization of the magnetic moments and by the gradual formation of a metal for the hypothetical compound Li2[NiN] (x = 1). XAS spectroscopy at the transition metal K‐edges shows that Cu and Ni principally correspond to d10‐ and d9‐configurations, respectively.

Synthesis, spectroscopic, and X-ray crystallographic characterisation of thorium(IV) and uranium(IV) malonato and substituted malonato compounds

Silica content influence on cement compressive strength in wells subjected to steam injection

X-ray crystallographic characterization of nilvadipine monohydrate and its phase transition behavior