Ammonium-exchanged phase of γ-titanium phosphate: Hydrothermal synthesis, crystal structure and thermal behavior

Resumen del póster presentado al 2nd Central and Eastern European Conference on Calorimetry and Thermal Analysis celebrado en Vilnius (Lituania) del 27 al 30 de agosto de 2013.Peer Reviewe

Synthesis and characterization of novel luminescent hybrid materials

Tesis doctoral presentada por Zakariae Amghouz dentro del Programa de Doctorado en Ciencia y Tecnología de Materiales de la Universidad de Oviedo.[ES]: En condiciones hidrotermales, se sintetizaron dos nuevos succinatos de itrio, Y2(C4H4O4)3(H2O)4·6H2O (2) y Y2(C4H4O4)3(H2O)2 (3). Sus estructuras cristalinas, resueltas a partir de datos de difracción de rayos X de monocristal se discutiron a la luz de la del Y2(C4H4O4)3(H2O)2·H2O (1). El estudio del comportamiento térmico de los tres compuestos fue posible como consecuencia de su obtención como fases individuales de elevada pureza. El sistema presenta gran diversidad estructural, consecuencia de los diferentes modos de coordinación y la flexibilidad conformacional del ligando succinato que, condicionada por la composición del medio de reacción, dirige la síntesis hacia el producto deseado. La síntesis de nuevos polímeros de coordinación quirales de itrio(III), [NaY(Tart)(BDC)(H2O)2] (1) y [NaY(Tart)(biBDC)(H2O)2] (2) (H2Tart = ácido tartárico; H2BDC = ácido tereftálico; H2biBDC = ácido bifenil-4,4'-dicarboxílico), con la participación de ligandos quirales flexibles y aquirales rígidos, también se efectuó en condiciones hidrotermales. 1 y 2 son compuestos quirales de simetría ortorrómbica, que cristalizan en idéntico grupo espacial (C2221): a = 6.8854(2) Å, b = 30.3859(7) Å, c = 7.4741(2) Å para 1, y a = 6.8531(2) Å, b = 39.0426(8) Å, c = 7.4976(2) Å para 2. Sus estructuras han sido resueltas utilizando la difracción de rayos X de monocristal, asistida por datos de resonancia magnética nuclear en estado sólido (13C CPMASNMR), análisis térmico (TG-MS y DSC) y análisis elemental. Ambos materiales poseen hábito laminar, alcanzando la estabilidad tridimensional mediante enlaces de hidrógeno interlaminares. Los estudios de termodifracción de rayos X de polvo cristalino (HTpXRD) desvelaron el mecanismo del proceso de deshidratación/rehidratación, siendo modelizadas la estructura de las fases anhidras. La sustitución de itrio por lantánidos trivalentes permitió la síntesis de dos nuevas series de compuestos: [NaLn(Tart)(BDC)(H2O)2] y [NaLn(Tart)(biBDC)(H2O)2] (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb). Estos materiales se caracterizaron mediante difracción de rayos X de monocristal y de polvo cristalino, análisis térmico (TG-MS y DSC), espectroscopia vibracional (FTIR), microscopia electrónica de barrido (SEMEDX), análisis elemental, y termodifracción de rayos X de polvo cristalino (HT-pXRD). Además de su actividad catalítica, es destacable el comportamiento fotoluminiscente de estos materiales, que presentan emisión sintonizable de luz UV-VIS-IR mediante una efectiva sensibilización de los cationes lantánidos trivalentes a través de los ligandos BDC2- y biBDC2-. irradiación por microondas, se utilizó como precursor en la síntesis hidrotermal de nuevos materiales híbridos organo-inorgánicos basados en metales lantánidos trivalentes (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). Se obtuvieron materiales monofásicos de composición Ln[O3P(C6H4)PO3H] (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho), aunque sólo en el caso del compuesto de praseodimio (Za1) ha sido posible aislar monocristales de calidad suficiente para su determinación estructural mediante difracción de rayos X de cristal único. Za1 tiene simetría monoclínica (grupo espacial C2/c), con a = 5.6060(4) Å, b = 20.251(7) Å, c = 8.2740(6) Å, ? = 108.52(1)º. Los demás compuestos anhidros de la serie son isoestructurales con Za1, y su estructura se refinó a partir de datos de difracción de rayos X de polvo cristalino. Sin embargo, los compuestos basados en Y, Er, Tm, Yb, y Lu cristalizan como fases hidratadas de estructura desconocida. Ambas series de compuestos se caracterizaron mediante análisis térmico (TG-MS, SDTA, y DSC), análisis elemental, espectroscopia infrarroja, termodifracción de rayos X de polvo cristalino (HT-pXRD), microscopia electrónica de transmisión (TEM) y de barrido (SEM-EDX). Estos materiales, que presentan tamaños de partícula variables (> 20 nm), exhiben una inusualmente alta estabilidad térmica. Todos ellos son paramagnéticos, con momentos magnéticos efectivos acordes con los esperados para cationes lantánidos en estado trivalente, mostrando fotoluminiscencia en la región visible del espectro electromagnético, con fuerte luminiscencia roja y verde, respectivamente, para los compuestos basados en europio y terbio.[EN]: Two new members in the yttrium-succinates family have been reported. These yttrium-succinates coordination polymers, formulated as Y2(C4H4O4)3(H2O)4·6H2O (2) and Y2(C4H4O4)3(H2O)2 (3), have been synthesized under hydrothermal conditions. Their structures solved by single crystal X-ray diffraction, are compared with that of Y2(C4H4O4)3(H2O)2·H2O (1). The three compounds were obtained as single phases, and their thermal behaviour is described. The results suggest that the structural diversity obtained in this system is related to the coordination diversity and the conformational flexibility of the succinate ligand, which in turn depend on the synthesis conditions that play an important role in directing to one compound or another. New chiral metal organic frameworks, assembled from Y(III), Na(I) and chiral flexible-achiral rigid dicarboxylate ligands, formulated as [NaY(Tart)(BDC)(H2O)2] (1) and [NaY(Tart)(biBDC)(H2O)2] (2) (H2Tart = Tartaric acid; H2BDC = Terephthalic acid; H2biBDC = Biphenyl-4,4'-dicarboxylic acid), were obtained as single phases under hydrothermal conditions. Their structures were solved by single-crystal X-ray diffraction, and characterized by 13C CPMAS NMR, thermal analyses (TG-MS and DSC), elemental analysis, and X-ray powder diffraction. Both compounds crystallize in the orthorhombic chiral space group C2221 with a = 6.8854(2) Å, b = 30.3859(7) Å, c = 7.4741(2) Å for 1, and a = 6.8531(2) Å, b = 39.0426(8) Å, c = 7.4976(2) Å for 2. 1 and 2 are layered structures whose three-dimensional stability is ensured by strong hydrogen bond interactions. The X-ray powder thermodiffractometry study was performed, and reveals that the dehydration of both compounds is accompanied by phase transformation, while the spontaneous rehydration process is characterized by different kinetics. The crystal structures of anhydrous compounds have been modeled. Two series of isoreticular chiral metal-organic frameworks assembled from Ln(III) (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb), Na(I), and chiral flexible-achiral rigid dicarboxylate ligands, formulated as [NaLn(Tart)(BDC)(H2O)2] and [NaLn(Tart)(biBDC)(H2O)2] (H2Tart = Tartaric acid; H2BDC = Terephthalic acid; H2biBDC = Biphenyl-4,4'-dicarboxylic acid), were obtained as single phases under hydrothermal conditions. The compounds have been studied by single-crystal and powder X-ray diffraction, thermal analyses (TG-MS and DSC), vibrational spectroscopy (FTIR), scanning electron microscopy (SEM-EDX), elemental analysis, and X-ray powder thermodiffractometry. The activity catalytic has been also investigated. Photoluminescence studies of the investigated materials show room temperature tunable UV-VIS-IR light emission through an effective Ln3+ sensitization via BDC2- and biBDC2- ligands. Series of novel organic-inorganic hybrids materials based on trivalent lanthanide (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and 1,4- phenylbis(phosphonate) has been obtained under hydrothermal conditions either by oven heat or microwave irradiation. Compounds based on La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Ho, formulated as Ln[O3P(C6H4)PO3H], has been obtained as single phases under hydrothermal conditions. In the praseodymium compound (Za1) single crystals have been obtained and the crystal structure determined. Za1 crystallizes in the monoclinic space group, C2/c, with a = 5.6060(4) Å, b = 20.251(7) Å, c = 8.2740(6) Å, β = 108.52(1)º. The compounds containing La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Ho, are anhydrous and isostructural to Za1 as confirmed by Rietveld refinement using X-ray powder diffraction data. However, the compounds based on Y, Er, Tm, Yb, and Lu are hydrated and their structures have not yet been solved. The series of compounds are characterized by thermal analyses (TG-MS, SDTA, and DSC), elemental analysis, IR spectra, X-ray powder diffraction, X-ray powder thermodiffractometry, transmission electron microscopy (TEM) and scanning electron microscopy (SEM-EDX). TEM study show a variable particles size with a minimum size of ca. 20 nm. These compounds exhibit unusual very high thermal stability. The size of particles and the thermal stability are depending on metal(III) cation features. All the investigated materials show paramagnetic behaviour. The magnetic susceptibility data follow a Curie-Weiss laws with paramagnetic effective moments in good agreement with those expected for Ln3+ free ions. The visible photoluminescence properties are also discussed. Eu- and Tb-based compounds exhibit strong red and green luminescence, respectively.Ministerio de Ciencia e Innovación por concederme una beca FPI (BES-2007-14340).Peer reviewe

Phase transformation on mixed yttrium/sodium-MOFs, X-ray thermodif-fractometry and structural modeling

6 páginas, 3 figuras, 1 tabla.-- Trabajo presentado como póster a la 12th European Powder Diffraction Conference (EPDIC 2010).New chiral MOFs, assembled from Y(III), Na(I) and chiral flexible-achiral rigid dicarboxylate ligands, have been obtained as single phase under hydrothermal conditions and their structures were solved by single-crystal XRD. The powder X-ray thermodiffractometry study was performed, and reveals that the dehydration of both compounds is accompanied by phase transformation, while the spontaneous rehydration process is characterized by different kinetics. The crystal structures of anhydrous compounds have been modeled.Financial support given by Spanish MICINN (MAT2006–01997, MAT2010-15094, Factoría de Cristalización–Consolider Ingenio 2010 and FPI grant BES-2007-14340 to Z. A.) and FEDER founding, are acknowledged.Peer reviewe

Synthesis and characterization of a new family of alkylammonium-chromium phosphates with worm-like morphology

A series of layered alkylammonium–chromium phosphates, formulated as [CnH2n+1NH3]Cr(OH)PO4 (n=2–6), has been synthesized under hydrothermal conditions. The interlayer spacing, increasing linearly with the increase of alkyl-chain length from 13.61 Å (n=2) to 21.20 Å (n=6), is occupied by a double sheet of packed amine molecules with a tilt angle of ca. 51° respect to the inorganic sheet. The powders are constituted by circular plates (diameter=0.5–3 µm, thickness=~50 nm) with central holes when n=4–6, stacked in axial direction showing worm-like morphologies. The presence of holes, and some corrugated and zig-zag fashions observed on the edge of thin circular plates are the most probable ways for the reduction of the steric tensions between organic and inorganic portions in these hybrid materials. The thermal and thermo-oxidative stability of selected compounds have been studied, including the determination of activation energy data for the decomposition processes.Financial support from Spanish Ministerio de Economía y Competitividad (MAT2010-15094, MAT2013-40950-R, Factoría de Cristalización – Consolider Ingenio 2010, and Técnicos de Infraestructuras Científico-Tecnológicas Grant PTA2011-4903-I to ZA) and FEDER founding is acknowledged.Peer Reviewe

Exfoliation and europium(III)-functionalization of α-titanium phosphate via propylamine intercalation: from multilayer assemblies to single nanosheets

Layered α-titanium phosphate intercalated with propylamine, Ti(HPO4)2·2C3H7NH2·H2O (α-TiPPr), has been synthesized by solid-vapour reaction and then exfoliated via a single-stage approach based on overnight stirring in aqueous medium. The obtained nanosheets were then functionalized using solid–liquid reaction with europium(III) nitrate aqueous solutions. The obtained materials were characterized by powder X-ray diffraction (PXRD), N2 adsorption–desorption isotherms at 77 K, scanning electron microscopy (SEM), transmission electron microscopy (TEM, SAED, STEM-EDX), atomic force microscopy (AFM) and photoluminescence spectroscopy (PL). The europium(III) sorption takes place via two distinct pathways, the first is the previously reported C3H7NH3+/[Eu(H2O)6]3+ ion-exchange process into the titanium–phosphate interlayer space of the multilayered α-TiPPr. The second pathway is the self-assembly of single-sheets which is provoked by electrostatic interactions between the negatively charged titanium–phosphate sheets and the Eu(III)-aqueous cations, leading to the formation of layered nanoparticles.Financial support from Spanish Ministerio de Economía y Competitividad (MAT2013-40950-R and MAT2016-78155-C2-1-R) and Gobierno del Principado de Asturias (GRUPIN14-060), and FEDER funding are acknowledged.Peer reviewe

α-Titanium phosphate intercalated with propylamine: An alternative pathway for efficient europium(III) uptake into layered tetravalent metal phosphates

α-Ti(HPO4)2·H2O (α-TiP) and its propylamine intercalation product, Ti(HPO4)2·2C3H7NH2·H2O (α-TiPPr), have been synthesized and characterized. Later, their sorption capacity for europium(III) was investigated, and this purpose was accomplished by treating α-TiP and α-TiPPr with europium(III) nitrate solutions at different concentrations until the equilibrium is reached. All samples were characterized, among others, by powder X-ray diffraction (PXRD), scanning and transmission electron microscopies (SEM, TEM, STEM-EDX, SAED), thermogravimetric analysis (TGA), and photoluminescence (PL) measurements. The results show that the Eu3+ uptake is limited to surface when α-TiP is used as sorbent. Nevertheless, the Eu-retention is considerably enhanced with α-TiPPr as a consequence of an ion-exchange process into the interlayer space of the layered titanium phosphate (involving propylammonium cations, C3H7NH3+, and hexahydrate europium(III) species, [Eu(H2O)6]3+), and the crystal structure of a hypothetical final product, α-[Eu(H2O)6]2/3Ti(PO4)2·[(H2O)6]1/3, has been proposed by using DFT calculations.Financial support from Spanish Ministerio de Economía y Competitividad (MAT2013-40950-R) and Gobierno del Principado de Asturias (GRUPIN14-060), and FEDER funding is acknowledged.Peer Reviewe

Crystal structure of (E)-3-(iodomethylene)-2,3-dihydro-[1,4]oxazino- [2,3,4-ij]quinolin-4-ium triodide —iodine (2:1), [C12H9INO]I3·0.5I2, C12H9I5NO

C12H9I5NO, triclinic, P1 (no. 2), a = 8.6099(5) Å, b = 9.7325(3) Å, c = 12.2098(6) Å, α = 108.972(4)°, β = 101.112(4)°, γ = 104.315(4)°, V = 894.9 Å3, Z = 2, Rgt(F) = 0.0373, wRref(F2) = 0.0581, T = 119 KWe thank for financial support from the Spanish Ministerio de Economía y Competitividad under projects MAT2010-15094, grant Técnicos de Infraestructuras Científico-Tecnológicas PTA2011-4903-I to Z. A. and FEDER. A. D. Also we thank to Spanish Ministerio de Educación, Cultura y Deporte for FPUgrant AP2008-03942. Thiswork was supported by Russian Foundation for Basic Research, grant 14-03-00961a.Peer reviewe

Nanolayered metal phosphates as biocompatible reservoirs for antimicrobial silver nanoparticles

This article belongs to the Special Issue Advances in Phosphate Materials: Structural, Technological and Biomedical Applications.There is an increasing demand on synthesizing pharmaceuticals and biomaterials that possess antimicrobial and/or antiviral activities. In this respective silver nanoparticles are known for their excellent antimicrobial activity. Nevertheless, their uncontrolled release in a biological medium can induce a cytotoxic effect. For this, we explored the use of nanolayered metal phosphates based on titanium and zirconium as materials that can be enriched with silver nanoparticles. Employing the hydrothermal route, crystalline α-phases of zirconium and titanium phosphates (α-ZrP, α-TiP) were synthesized and there after surface-enriched with silver nanoparticles. The structural assessment confirmed the stability of the structures and their sizes are in the nanoscale at least in one dimension. The cytocompatibility assays confirmed the biocompatibility of the pristine phases and the antimicrobial assay confirmed that both silver-enriched nanolayered structures maintain an antibacterial effect at reasonably low concentrations.This research was funded by MINECO, grant number MAT2016-78155-C2-1-R and by the Government of the Principality of Asturias, grant number GRUPIN-IDI/2018/170.Peer reviewe

Biogenic amines in wine: Individual and competitive adsorption on a modified zirconium phosphate

A commercial zirconium phosphate was subjected to annealing in NaCl–NaOH aqueous solution until pH 3.2. The new material (Na-ZrP) and its n-butylamine intercalation product were characterized, among others, by powder X-ray diffraction, solid-state nuclear magnetic resonance, and high resolution transmission electron microscopy, being Na-ZrP a non-porous polyphasic semicrystalline material, constituted mainly of plate-shaped particles with domains of α-Zr(HPO4)2·H2O and α-Zr(NaPO4)(HPO4)·nH2O type. Na-ZrP was tested as an adsorbent for elimination of biogenic amines (histamine, putrescine, cadaverine, and tyramine) in synthetic wine. Among the studied amines, histamine is the fastest adsorbed (individually and competitively), followed by cadaverine, putrescine and tyramine. All of them present L2-type individual isotherms. Competitive isotherms are also L2-type except cadaverine (L-Max) and tyraminte (Type C). Histamine and putrescine are the amines absorbed in higher amounts. The results from adsorption isotherms and kinetic measurements (individual and competitive) fit the adsorption classical models showing that the preferential adsorption mechanism is the ion-exchange of the cationic amines with Na+ cations present in the adsorbent, being not discarded that some amines could be joined by hydrogen bonds.The authors thank FEDER and Spanish MINECO for financial support under projects MAT2010-15094, and Técnicos de Infraestructuras Científico-Tecnológicas grant PTA2011-4903-I to ZA and PTA2011-4950-I to SAK.Peer Reviewe

Evaluation of hydrogen trapping and diffusion in two cold worked CrMo(V) steel grades by means of the electrochemical hydrogen permeation technique

Hydrogen diffusion kinetics, which is influenced by the hydrogen trapping and de-trapping phenomena within the steel microstructure, plays an important role on the behaviour of steel components under hydrogen environments. Hence, the complex interaction between hydrogen atoms and steel microstructure must be analyzed in order to discuss the impact of hydrogen on the structural damage. Quenched and tempered low-alloy ferritic steels from the Cr-Mo family, with and without vanadium, have been subjected to different plastic deformation ratios by cold rolling. Dislocation densities have been determined by the analysis of the peak broadening on X-Ray diffractograms. Hydrogen diffusion kinetics was characterized by means of hydrogen permeation transients. In addition, binding energies between hydrogen atoms and microstructure were also determined using thermal desorption analysis (TDA). The analysis of the results highlights the influence of dislocations density and vanadium carbides on the hydrogen diffusion kinetics. In the 2.25Cr1Mo steel grade, hydrogen apparent diffusion coefficient decreased after the cold-work due to the increase in the density of traps (mainly related to dislocation core, ΔETL = 55–60 kJ/mol). Nevertheless, after 10% of plastic deformation, apparent diffusion coefficient ‘saturates’ according to the ‘plateau’ determined in the dislocation density evolution at higher deformation levels. Due to the vanadium addition (+0.31%), hydrogen apparent diffusion coefficient was notably reduced (compared to that obtained in the V-free steel grade). Hydrogen trapping and diffusion are the result of the interplay between vanadium carbides (ΔETL = 35 kJ/mol) and dislocation core