Synthesis and characterization of a new mebendazole salt: mebendazole hydrochloride.

Mebendazole hydrochloride [(5-benzoyl-1H-benzimidazole-2-yl)-carbamic acid methyl ester hydrochloride, MBZ.HCl], a new stable salt of mebendazole (MBZ), has been synthesized and characterized. It can easily be obtained from recrystallization of forms A, B, or C of MBZ in diverse solvents with the addition of hydrochloric acid solution. Crystallographic data reveals that the particular conformation adopted by the carbamic group contributes to the stability of the network. The crystal packing is stabilized by the presence of three N-H...Cl intermolecular interactions that form chains along the b axis. The XRD analyses of the three crystalline habits found in the crystallization process (square-based pyramids, pseudohexagonal plates, and prismatic) show equivalent diffraction patterns. The vibrational behavior is consistent with crystal structure. The most important functional groups show shifts to lower or higher frequencies in relation to the MBZ polymorphs. The thermal study on MBZ.HCl indicates that the compound is stable up to 160 degrees C approximately. Decomposition occurs in four steps. In the first step the HCl group is eliminated, and after that the remaining MBZ polymorph A decomposes in three steps, as happens with polymorphs B and C. (

Tuning the target composition of amine-grafted CPO-27-Mg for capture of CO2 under post-combustion and air filtering conditions: a combined experimental and computational study.

A computational and experimental screening of hypothetical and real compounds exhibiting different degrees of ethylenediamine grafted to the CPO-27-Mg or Mg-DOBDC skeleton is performed in order to determine the target composition that optimizes the CO2 adsorption properties under flue gas and air filtering conditions. On the basis of the [Mg2(dobdc)] formula, eighteen hypothetical models involving 15-100% of functionalization of the coordinatively unsaturated sites (CUS) were considered by means of Grand Canonical Monte Carlo simulations to evaluate the CO2 adsorption at 298 K. In addition, post-synthesis modification was applied to CPO-27-Mg leading to three kinds of samples exhibiting 15, 50, and 60% of CUS functionalization with ethylenediamine, named CPO-27-Mg-a, CPO-27-Mg-b and CPO-27-Mg-c. Compounds were characterized using elemental analysis, TGA, FTIR spectroscopy, PXRD and DSC. Finally, bare and functionalized CPO-27-Mg materials were evaluated using gas adsorption and microcalorimetry in the 0.001-1 bar range, which is pertinent for the mentioned applications. Valuable information related to design criteria for synthesis of tuned CO2 adsorbents is derived through this computational and experimental investigation.

Layered exfoliable crystalline materials based on Sm-, Eu- and Eu/Gd-2-phenylsuccinate frameworks. Crystal structure, topology and luminescence properties.

Three new layered metal-organic frameworks (MOFs) based on 2-phenylsuccinic acid (H2psa) and lanthanide ions with the formula [Ln2(C10H8O4)3(H2O)] (Ln = Eu, Sm and Eu-Gd) have been synthesized under solvothermal conditions and fully characterized by single-crystal X-ray diffraction, thermal and vibrational analyses. The compounds are isostructural featuring 2D frameworks that consist of infinite zigzag chains composed of [LnO8] and [LnO8(H2O)] edge-sharing polyhedra linked by psa ligands leading to layers further connected by weak π-π interactions in an edge orientation. Moreover, a topological study was carried out to obtain the simplified net for better comparison with structurally related compounds. The crystals were exfoliated into nanolayers after miniaturization by addition of sodium acetate as a capping agent in the reaction medium. Scanning electron microscopy was applied to characterize the miniaturized samples whereas the exfoliated hybrid nanosheets were studied by atomic force microscopy. The photoluminescence (PL) properties of the bulk compounds as well as the miniaturized and exfoliated materials were investigated and compared with other related ones. An exhaustive study of the Eu(iii)-based MOFs was performed on the basis of the obtained PL parameters (excitation and emission spectra, kr, knr, intrinsic quantum yields and lifetimes) to explore the underlying structure-property relationships.

Removal of oxovanadium(IV) from aqueous solutions by using commercial crystalline calcium hydroxyapatite.

The interaction of oxovanadium(IV) (VO(2+)) in aqueous solution with commercial calcium hydroxyapatite (CAP) has been studied. VO(2+) ions are adsorbed on the surface of CAP by coordination to OH groups, without modification of the crystalline lattice. The extent of the adsorption is followed by chemical analysis, ESR and IR spectroscopy. Results are compared with those obtained for VO(2+)/synthetic calcium hydroxyapatite (HAP), reported by us in previous works. The uptake is better than the observed for HAP. The maximum adsorption is observed at pH 3.5 and 288 K. We conclude that VO(2+) is indeed adsorbed on CAP and the extent of adsorption depends on the pH and temperature.

A low temperature infrared study of the coordinated water in calcium malonate dihydrate.

The infrared spectra of calcium malonate dihydrate in the polycrystalline state, both normal and with different degrees of deuteration, were obtained at low temperatures in order to obtain information about the crystalline environment of the hydration water molecules. The study showed that both water molecules are non-equivalent and non-symmetric. That result is indicative of a non-symmetric space group for the crystal, in agreement with one out of three different crystallographic studies made on the substance.