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Although the fibrous polymorphic modification of titanium phosphate, π-Ti2O(PO4)2·2H2O (π-TiP) is known for decades, its crystal structure has remained unsolved. Herewith we report the crystal structure of π-TiP at a room temperature, determined from the synchrotron radiation powder X-ray diffraction, and corroborated by 31P solid state NMR and the accurate density functional theory calculations. In contrast to the previously reported ρ-TiP polymorph, the as-synthesized hydrated phase crystallizes in the monoclinic system (P21/c, a = 5.1121(2) Å, b = 14.4921(9) Å, c = 12.0450(11), β = 115.31(1)°, Z=4) and is composed of corner-sharing titanium octahedra and phosphate units arranged in a pattern distinct of ρ-TiP polymorph. The unit cell was confirmed by SAED, while the formation of planar packing imperfections and stacking faults along the [101] was revealed by HRTEM analysis. In situ dehydration study of π-TiP, monitored by high-temperature powder X-ray diffraction, led to a new anhydrous monoclinic [P21/c, a = 5.1187(13) Å, b = 11.0600(21) Å, c = 14.4556(26), β = 107.65(2)°, Z=4) phase that crystallizes at 500°C. The latter resembles the packing fashion of the parental π-TiP, albeit titanium atoms are present both in distorted tetrahedral and octahedral coordination environments. Anhydrous π-TiP was found to partially rehydrate at room temperature adopting reversibly the structure of the initial phase. The studies carried out under different conditions of leaching and impregnation with H3PO4 showed that π-TiP exhibits an extrinsic proton conductivity (1.3·10−3 S·cm−1 at 90 °C and 95% RH) due to the presence of protonated phosphate species bounded on the particles surface, as revealed by 31P MAS-NMR spectroscopy data. The composite membranes of Chitosan (CS) matrices filled with H3PO4-impregnated π-TiP solid show an increment of proton conductivity up to 4.5·10–3 S·cm–1, at 80 °C and 95% RH, 1.8-fold higher than those of bare CS membranes MAT2016-77648-R and PID2019-110249RB-I00), Junta deAndalucía (FQM-113) M. Bazaga-García thanks Junta de Andalucía for her Postdoc PAIDI grant and R. M. P. Colodrero thanks UMA Research Plan for her financial support.

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. During the last decade, the synthesis and application of metal-organic framework (MOF) nanosheets has received growing interest, showing unique performances for different technological applications. Despite the potential of this type of nanolamellar materials, the synthetic routes developed so far are restricted to MOFs possessing layered structures, limiting further development in this field. Here, a bottom-up surfactant-assisted synthetic approach is presented for the fabrication of nanosheets of various nonlayered MOFs, broadening the scope of MOF nanosheets application. Surfactant-assisted preorganization of the metallic precursor prior to MOF synthesis enables the manufacture of nonlayered Al-containing MOF lamellae. These MOF nanosheets are shown to exhibit a superior performance over other crystal morphologies for both chemical sensing and gas separation. As revealed by electron microscopy and diffraction, this superior performance arises from the shorter diffusion pathway in the MOF nanosheets, whose 1D channels are oriented along the shortest particle dimension.

Resumen del trabajo presentado al congreso Nanomaterials applied to Life Sciences (NALS), celebrado en Gijón (España) del 13 al 15 de diicembre de 2017., Silver is a metal known for its antimicrobial activity against Gram-positive and Gram-negative bacteria, including antibiotic-resistant strains, fungi, protozoa and certain viruses. It is used for treatment of infections, preventing bacterial colonization on medical devices and for water treatment. Silver, as an antiseptic agent, is efficient while present in glass, titanium and polymers. This motivates its use in biomedical applications, water and air purification, food production, cosmetics, clothing and numerous household products. Titanium and its alloys were widely used as artificial joints, bone fixation devices or dental implants, in orthopedic field, mainly due to their great mechanical properties, corrosion resistance and biocompatibility. However, some shortcomings of native titanium were found to hinder its osteointegration and even affect the long-term survival of Ti-based implants. The deposition of nanostructured thin films of certain inorganic compounds on the surface of a metal, thus creating thin film/metal composites, is of particular interest in this field. It has been shown that the materials composed of titanium-based coatings on the Ti-metal surfaces can be used as implants with excellent apatite-forming and antibacterial abilities. Recently, the surface wettability control has attracted significant attention because of the promising applications of superhydrophobic and superhydrophilic materials for self-cleaning, corrosion resistant, fluidic drag reduction, and oil-water separation. In this way, Yada et al. has reported the superhydrophilicity and superhydrophobicity properties of π-titanium phosphate nanorod thin films modified with alkylamine molecules (the first synthesis of π-Ti2O(PO4)2·2H2O was reported by our Lab in the end of the last century), while Lu has described the thin film preparation composed of π-titanium phosphate nanorods by performing a hydrothermal treatment of a titanium plate in phosphoric acid solution at 250 °C. Finally, Park et al. by performing a hydrothermal treatment of the titanium plate in phosphoric acid solution at 180 °C has also obtained a π-titanium phosphate thin film of approximately 5 μm thick and having needle-like surface microstructures. In this context, the present communication is devoted to the ability of π-titanium phosphate to the intra-crystalline incorporation of silver(I) cations as a way for the trapping of bioactive metals into a neutrally charged framework, with the consecutive incorporation of the produced material into titanium (and titanium alloys) surfaces., We thank the Spanish MINECO (MAT2013-40950-R, MAT2016-78155-C2-1-R) and FEDER for financing.

Resumen del póster presentado al 29th European Crystallographic Meeting, celebrado en Rovinj (Croacia) del 23 al 28 de agosto de 2015., We thank financial support from Spanish Ministerio de Economía y Competitividad (MINECO-13-MAT2013-40950-R, FP1 grant BES-2011-046948 to MSM-A and Técnicos de Infraestructuras Científico-Tecnológicas grant PTA2011-40903-I to Z-A) and ERDF.

The monoammonium salt of γ-titanium phosphate has been prepared by hydrothermal treatment of π-Ti2O(PO4)2·2H2O in the presence of urea and phosphoric acid, and its crystal structure was obtained by Rietveld analysis using powder X-ray diffraction data. γ-Ti(PO4)(NH4HPO4) crystallizes in the monoclinic space group P21/m with a = 5.0725(3) Å, b = 6.3101(3) Å, c = 11.2435(5) Å, β = 97.980(3)° (Z = 2). The structure consists of 2D titanium phosphate layers in the ab-plane. The titanium atoms and one of the phosphate groups are located nearly in the ab-plane of the layer. All the oxygen atoms of this phosphate group are involved in titanium coordination sphere. The other phosphate group located in the layers edges links two neighboring titanium atoms in the a-direction through two of its oxygen atoms. The remaining two oxygens are pointed toward the interlayer space being involved in hydrogen bond interactions with the ammonium ions. Each ammonium ion is shared by four oxygens belonging to four different phosphate hydroxyl groups. γ-Ti(PO4)(NH4HPO4) is stable until 453 K, while above this temperature, it transforms to γ’-Ti(PO4)(NH4HPO4) high temperature polymorph stable until 573 K. Thermal decomposition of this material leads to cubic TiP2O7 structure, with previous formation of two intermediate pseudo-layered compounds: Ti(PO4)(NH4HP2O7)0.5 and Ti(PO4)(H2P2O7)0.5. The activation energy of thermal decomposition has been calculated as a function of the extent of conversion applying the Kissinger–Akahira–Sunose (KAS) isoconversional method to the thermogravimetric data., We thank financial support from Spanish MINECO (MAT2010-15094, MAT2011-27573-C04, Factoría de Cristalización – Consolider Ingenio 2010, Técnicos de Infraestructuras Científico-Tecnológicas Grant PTA2011-4903-I to ZA, and PTA2011-4950-I to SAK) and FEDER.

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).

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.

Programa de Doctorado en Materiales., This work is supported by Ministerio de Economía y Competitivdad (MAT2016-78155-C2-1-R, MAT2013-40950-R, MAT2011-27573-C04-02, Gobierno del Principado de Asturias (GRUPIN14-060), and FEDER.

Graphitic carbon nitride assisted partial photocatalytic oxidation of 5-hydroxymethyl-2-furfural (HMF) in aqueous medium was investigated. Different carbon nitride precursors were considered, being melamine the one yielding the most efficient photocatalyst. The obtained 30% selectivity of HMF oxidation to 2,5-furandicarboxaldehyde (FDC) is higher than those reported up to now. A further thermal exfoliation of the g-C3N4 samples showed under artificial light irradiation both an enhanced photocatalytic activity in conversion of HMF, and selectivity (ca. 42–45%) to FDC. The performance of the catalysts increased when the experiments were carried out under real outdoor illumination, reaching 50% of selectivity versus FDC formation at 40% of HMF conversion. The utilization of radical scavengers revealed that O2− was the main reactive species responsible for HMF oxidation to FDC. The photocatalytic test carried out under natural solar irradiation resulted in higher yields of FDC compared to that observed in the laboratory UV irradiated set-up, thus demonstrating the applicability of the exfoliated carbon nitride material in real-life conditions., University of Oviedo gratefully acknowledges financial support from the MINECO (MAT2013-40950-R), FEDER-FICyT (GRUPIN14-060) and CTQ2014-52956-C3-1-R. IK thanks for the support the Ministry of Education and Science of the Russian Federation (grant No 16.2674.2014/K).