Ozonation enhancement by Fe-Cu bimetallic particles

The aim of this work was to assess the effect of the bimetallic system Fe–Cu on the ozonation efficiency of indigo carmine and its main degradation product, isatin-5-sulfonic acid. As reference, experiments with single metal particles were also conducted. The metallic systems were synthesized by a chemical reduc- tion method and characterized by EPR and HR-SEM/EDS. Cu and Fe oxidation states were found to be 2 + . The ozonation process was carried out in an up-flow bubble column. The organic compounds concentra- tion was determined by UV–vis spectroscopy. The degree of oxidation and mineralization was determined by COD and TOC measurements, respectively. The effect of pH was also studied. It was found that the use of the bimetallic system not only considerably (by three times) improves the ozonation rate but also the mineralization degree of indigo carmine. The best results (97% indigo carmine removal and 92% of TOC removal) were obtained at pH 3 and with 10 0 0 mg/l of Fe/Cu particles.PRODEP 03.5/13/5257 y CONACY

Structure of a Luminescent MOF-2 Derivative with a Core of Zn(II)-Terephthalate-Isoquinoline and Its Application in Sensing of Xylenes

Articulo de investigación publicado en revista indexada.A new blue photoluminescent 2D metal–organic framework, 1, with formula {[Zn2( 2-BDC)2 (iQ)2]}1 has been synthesized in a high yield under solvothermal conditions by reacting Zn(II) ions with 1,4-benzenedicarboxylic acid (H2BDC) and isoquinoline (iQ) in DMF. Compound 1 was thoroughly characterized by single-crystal X-ray di raction, solid-state cross-polarization magic-angle spinning 13C NMR, X-ray powder di raction, scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), and thermoanalysis. The crystal structure of 1 showed interpenetrated 2D frameworks consisting of dinuclear paddle-wheel cores Zn2; moreover, this material possessed thermostability up to 310 C. The CPMAS 13C-NMR spectrum of 1 is consistent with the symmetry of the crystal structure. Luminescence studies showed that 1 strongly enhances its fluorescence emission in the presence of xylene isomers with a pronounced selectivity to p-xylene.Universidad Autónoma del Estado de México (Project 4995/2020CIB

Chemosensing of Chloride Based on a Luminescent Platinum(II) NCN Pincer Complex in Aqueous Media

The new luminescent platinum­(II) pincer complex [Pt­(NCN)­(S)]­TfO (<b>I</b>; NCN = 1,3-bis­(2-<i>N</i>-phenylbenzimidazolyl)­benzene, S = solvent, and TfO^– = triflate anion) was synthesized and studied as a chemosensor for chloride in aqueous media. In 50 vol % aqueous DMF or CH₃CN chloride quenches the fluorescence with association constants of 1.2 × 10³ and 81 M^–1, respectively. On the other hand, in the micellar medium of cetyltrimethylammonium hydrogensulfate at pH 7.0 additions of inorganic anions to <b>I</b> enhance the fluorescence with a pronounced selectivity toward chloride, which shows also much tighter binding to the receptor with association constant 7.9 × 10⁴ M^–1 in comparison to that in mixed organic solvents. On basis of ¹H NMR titration experiments and the crystal structure of the neutral chloro complex of <b>I</b> the binding mode of chloride is proposed involving the coordination of chloride to the Pt­(II) atom with simultaneous formation of intramolecular short C–H···Cl–Pt contacts. The combination of the cyclometalated platinum complex <b>I</b> with a cationic surfactant allows for the detection of chloride in the micromolar concentration range in samples of bottled mineral water

Synthesis of Metforminium Succinate by Melting. Crystal Structure, Thermal, Spectroscopic and Dissolution Properties

The reaction by melt mixing at 220 °C of the antihypergly-cemic drug metformin hydrochloride1with dehydrated sodium suc-cinate yields efficiently the organic salt [MET]2[SUC]2(H-MET+=metforminium and SUC2-= succinate). Solid state CPMAS NMR13Cspectroscopy experiments, powder X-ray diffraction and FT-IR re-sults support the formation of the pharmaceutical salt2in goodyields. Besides, thecharged-assisted hydrogen bonding interactionsof type N-H...-O(carboxylate) were thoroughly analyzed by singlecrystal X-Ray diffraction techniques. Thus, the pharmaceutical salt2possesses considerable thermal differences when compared to thepure starting reagents. In addition, intrinsic dissolution rate expe-riments in buffered aqueous solutions at pH= 6.8 showed a sus-tained-release behavior of the drug in2with a constant value ofKint= 0.885 mg/min * cm2

Dinuclear complexes of Mn, Co, Zn and Cd assembled with 1,4-cyclohexanedicarboxylate: synthesis, crystal structures and acetonitrile fluorescence sensing properties

Articulo cientifico publicado en revista indexada.Four dinuclear complexes: [Mn2(H2O)2(chdc)2(bipy)2], 1; [Co2(H2O)2(chdc)2(bipy)2] H2O, 2; [Zn2(H2O)2(chdc)2- (bipy)2] H2O, 3; and [Cd2(H2O)2(chdc)2(bipy)2] H2O, 4; chdc = e,a-cis-1,4,cyclohexanedicarboxylate and bipy = 2,20-bipyridine, were attained as single crystals under ambient conditions. Crystallographic studies show that complexes 1, 2 and 3 are isostructural and crystallize in the monoclinic system with the P21/c space group. The metal centers in these complexes are hexa-coordinated with a distorted octahedral coordination sphere. Complex 4 crystallizes in the triclinic system with the P%1 space group; in this compound, the metal centers are hepta-coordinated and their coordination sphere is distorted-capped trigonal prismatic. Magnetic property measurements reveal that complexes 1 and 2 exhibit weak antiferromagnetic ordering. Complex 4 displays solid-state blue emission properties and a highly sensitive response to acetonitrile in water based on turn-on fluorescence with a low detection limit of 1.1 mM and selectivity over common polar organic solvents.Universidad Autonoma del Estado de Mexico (project 4995/2020CIB)

Synthesis and Characterization of Ag-Modified V2O5 Photocatalytic Materials

V2O5 powders modified with different theoretical silver contents (1, 5, 10, 15, and 20 wt% as Ag2O) were obtained with acicular morphologies observed by scanning electron microscopy (SEM). Shcherbinaite crystalline phase is transformed into the Ag0.33V2O5 crystalline one with the incorporation and increase in silver content as was suggested by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. With further increase in silver contents the Ag2O phase appears. Catalysts were active in photocatalytic degradation of malachite green dye under simulated solar light, which is one of the most remarkable facts of this work. It was found that V2O5-20Ag was the most active catalytic formulation and its activity was attributed to the mixture of coupled semiconductors that promotes the slight decrease in the rate of the electron-hole pair recombination