Proton conductivity and luminiscence properties of lanthanide aminotriphosphonates

Metal phosphonates are multifunctional solids with tunable properties, such as internal H-bond networks, and high chemical and thermal stability [1]. In the present work, we describe the synthesis, structural characterization, luminescent properties and proton conduction performance of a new family of isostructural cationic compounds with general formula [Ln(H4NMP)(H2O)2]Cl·2H2O [Ln = La3+, Pr3+, Sm3+, Gd3+, Tb3+, Dy3+, Ho3+, H6NMP = nitrilotris(methylphosphonic acid)]. These solids are formed by positively charge layers, which consist of isolated LnO8 polyhedra and bridge chelating NMP2- ligands, held apart by chloride ions and water molecules. This arrangement result in extended interlayer hydrogen networks with possible proton transfer pathways. The proton conductivity of Gd3+ sample, selected as prototype of the series, was measured. In the range between range 25º and 80 ºC, the conductivity increase with the temperature up to a maximum value of 3.10-4 S·cm-1, at relative humidity of 95 %. The activation energy obtained from the Arrhenius plot (Figure 1) is in the range corresponding to a Grotthuss transfer mechanism.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. FQM-1656; MAT2013-41836-R

Crystal engineering in confined spaces. A novel method to grow crystalline metal phosphonates in alginate gel systems

In this paper we report a crystal growth method for metal phosphonate frameworks in alginate gels. It consists of a metalcontaining alginate gel, in which a solution of phosphonate ligand is slowly diffused. Crystals of metal phosphonate products are formed inside the gel. We have applied this for a variety of metal ions (alkaline-earth metals, transition metals and lanthanides) and a number of polyphosphonic acid and mixed carboxy/phosphonic acid ligands.Proyecto nacional MAT2010-1517

Luminescent and Proton Conducting Lanthanide Coordination Networks Based On a Zwitterionic Tripodal Triphosphonate

The synthesis, structural characterization, luminescence properties, and proton conduction performance of a new family of isostructural cationic 2D layered compounds are reported. These have the general formula [Ln(H4NMP)- (H2O)2]Cl·2H2O [Ln = La3+, Pr3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, H6NMP = nitrilotris(methylphosphonic acid)], and contain Cl− as the counterion. In the case of Ce3+, a 1D derivative, [Ce2(H3NMP)2(H2O)4]·4.5H2O, isostructural with the known lanthanum compound has been isolated by simply crystallization at room temperature. The octa-coordinated environment of Ln3+ in 2D compounds is composed by six oxygen atoms from three different ligands and two oxygens from each bound water. Two of the three phosphonate groups act as both chelating and bridging linkers, while the third phosphonate group acts solely as a bridging moiety. The materials are stable at low relative humidity at less at 170 °C. However, at high relative humidity transform to other chloride-free phases, including the 1D structure. The proton conductivity of the 1D materials varies in a wide range, the highest values corresponding to the La derivative (σ ≈ 2 × 10−3 S·cm−1 at RH 95% and 80 °C). A lower proton conductivity, 3 × 10−4 S·cm−1, was measured for [Gd(H4NMP)(H2O)2]Cl·2H2O at 80 °C, which remains stable under the work conditions used. Absorption and luminescence spectra were recorded for selected [Ln(H4NMP)(H2O)2]Cl·2H2O compounds. In all of them, the observed transitions are attributed solely to f−f transitions of the lanthanide ions present, as the H4NMP2− organic group has no measurable absorption or luminescence properties.Proyecto nacional MAT2013-41836-R (MINECO) y Proyecto de la Junta de Andalucía P12-FQM-165

High-Throughput Synthesis of Pillared-Layered Magnesium Tetraphosphonate Coordination Polymers: Framework Interconversions and Proton Conductivity Studies

Novel pillared-layered framework materials were synthesized by high-throughput or microwave-assisted methodology that contain Mg2+ and the zwitterionic linker HDTMP (hexamethylenediamine-N,N,N0,N0-tetrakis(methylenephosphonic acid)). Three compounds were structurally characterized by X-ray powder diffraction. In the compound {Mg[(HO3PCH2)2N(CH2)6N (CH2PO3H2)2](H2O)}n(1), obtained at 140 ºC by hydrothermal or microwave-assisted reaction, the layers are built by isolated Mg2+ octahedra coordinated by oxygen atoms from six different zwitterionic HDTMP ligands. Each amino-bis(methylenephosphonate) moiety links three Mg2+ ions, bridging two of them through one phosphonate group and connecting the third polyhedron in a monodentate fashion. In Compound 2, {Mg[(HO3PCH2)2N(CH2)6N(CH2PO3H2)2]}n, hydrothermally synthesized at 180 C, the layers are composed of bidentate amino-bis(methylenephosphonate) moieties connected to three Mg2+ ions, with one of the phosphonate groups acting as a bridging ligand. Various subtle structural changes are noted for the other two compounds. Thermodiffraction of 1 reveals that a crystalline-to-crystalline phase transformation occurs concomitantly with its dehydration, leading to a new anhydrous phase, namely, {Mg[(HO3PCH2)2N(CH2)6N(CH2PO3H2)2]}n(1deh). This process is fully reversible upon equilibrating the solid at room temperature. The reported compounds can adsorb ammonia and CO2. Compound 1 exhibits a moderate proton conductivity, ~1.5 x 10-5 S·cm-1 at 80 ºC and 95% RH, that increases a half order of magnitude after experiencing a complete dehydration/rehydration process

Divalent Metal Vinylphosphonate Layered Materials: Compositional Variability, Structural Peculiarities, Dehydration Behavior, and Photoluminescent Properties

A family of M-VP (M = Ni, Co, Cd, Mn, Zn, Fe, Cu, Pb; VP = vinylphosphonate) and M-PVP (M = Co, Cd; PVP = phenylvinylphosphonate) materials have been synthesized by hydrothermal methods and characterized by FTIR, elemental analysis, and thermogravimetric analysis (TGA). Their structures were determined either by single crystal X-ray crystallography or from laboratory X-ray powder diffraction data. The crystal structure of some M-VP and M-PVP materials is two-dimensional (2D) layered, with the organic groups (vinyl or phenylvinyl) protruding into the interlamellar space. However, the Pb-VP and Cu-VP materials show dramatically different structural features. The porous, three-dimensional (3D) structure of Pb-VP contains the Pb center in a pentagonal pyramid. A Cu-VP variant of the common 2D layered structure shows a very peculiar structure. The structure of the material is 2D with the layers based upon three crystallographically distinct Cu atoms; an octahedrally coordinated Cu2+ atom, a square planar Cu2+ atom and a Cu+ atom. The latter has an unusual co-ordination environment as it is 3-coordinated to two oxygen atoms with the third bond across the double bond of the vinyl group. Metal-coordinated water loss was studied by TGA and thermodiffractometry. The rehydration of the anhydrous phases to give the initial phase takes place rapidly for Cd-PVP but it takes several days for Co-PVP. The M-VP materials exhibit variable dehydration-rehydration behavior, with most of them losing crystallinity during the process.Proyecto nacional MAT2010-15175 (MICINN, España

Structural Systematics and Topological Analysis of Coordination Polymers with Divalent Metals and a Glycine-Derived Tripodal Phosphonocarboxylate

A novel family of four hybrid metal phosphonate coordination polymers is reported that are constructed from divalent metal ions (Ca, Sr, Ba, and Pb) and <b>BPMGLY</b> (bis-phosphonomethylglycine, a phosphonated derivative of glycine). These compounds (and their compositions) are <b>Ca-BPMGLY</b> (CaBPMGLY·H₂O), <b>Sr-BPMGLY</b> (SrBPMGLY·H₂O), <b>Ba-BPMGLY</b> (Ba_3.5(BPMGLY)₂·6H₂O), and <b>Pb-BPMGLY</b> (PbBPMGLY·H₂O). They were obtained by hydrothermal reactions in acidic aqueous solutions (pH range 2.3–5.7) and fully characterized by physicochemical methods and structural analysis. <b>Ca-BPMGLY</b>, <b>Sr-BPMGLY</b>, and <b>Pb-BPMGLY</b> have very similar 3D coordination polymer structures, and the latter two are isostructural. In contrast to the Ca, Sr, and Pb analogs, <b>Ba-BPMGLY</b> possesses a different 2D layered network. These four new compounds, together with our previously reported 2D coordination polymer <b>Mg-BPMGLY</b> (MgBPMGLY·2H₂O, Demadis et al.<i> Inorg. Chem.</i> <b>2012</b>, 51, 7889–7896), were topologically classified revealing (i) the uninodal 3-connected net with the <b>hcb</b> topology in <b>Mg-BPMGLY</b>, (ii) the uninodal 5-connected nets with the <b>bnn</b> and <b>vbj</b> topology in <b>Ca-BPMGLY</b> and <b>Sr-BPMGLY</b>, respectively, and (iii) the very complex topologically unique hexanodal 4,4,6,6,7,8-connected net in <b>Ba-BPMGLY</b>. The <b>vbj</b> topology was also identified in the related <b>Pb-BPMGLY</b> 3D framework. These topological features show that the complexity of BPMGLY-driven 2D and 3D metal–organic networks increases periodically following the Mg < Ca ≤ Sr ≪ Ba trend

Physical Improvement and Biological Maturity of Young Athletes (11-12 Years) with Systematic Training

AIM: The aim of this study was to investigate the infl uence of systematic training in physical growth and biological maturity in prepubertal males and estimate how this affects the physical growth and skeletal maturity. MATERIALS AND METHODS: 177 primary school students of the fifth and sixth grade, from schools in Alexandroupolis, participated voluntarily in our study. Questionnaires were used in order to measure physical activity levels. The subjects were subdivided into two groups; control group (prepubertal, whose physical activity was the physical education of their school and which had never participated in systematic training, n = 95) and experimental group (prepubertal, whose weekly physical activity included physical education in their schools and additionally 3-4 training units organized training in various sports clubs in the city, n = 82). The following parameters were recorded: biological age measured by determination of skeletal age; bone density measured by ultrasound methods; anthropometric and morphological features such as height, body composition, selected diameters, circumferences and skinfolds; motor ability features. RESULTS: The experimental group exhibited older biological age (p = 0.033), higher bone density (p < 0.001), lower BMI and body fat (p < 0.001), better anthropometric features and higher performance throughout all motor ability tests (p < 0.05), compared to the control group. CONCLUSION: The present study demonstrates that systematic physical activity has a positive effect on both the physical and biological maturity of pre-pubertal children. This effect is mainly expressed in bone strengthening as a result of the increased bone density and in improvement of the kinetic skills of pupils who participated in organized extracurricular sport-activities

Molecular Insights in Atrial Fibrillation Pathogenesis and Therapeutics: A Narrative Review

The prevalence of atrial fibrillation (AF) is bound to increase globally in the following years, affecting the quality of life of millions of people, increasing mortality and morbidity, and beleaguering health care systems. Increasingly effective therapeutic options against AF are the constantly evolving electroanatomic substrate mapping systems of the left atrium (LA) and ablation catheter technologies. Yet, a prerequisite for better long-term success rates is the understanding of AF pathogenesis and maintenance. LA electrical and anatomical remodeling remains in the epicenter of current research for novel diagnostic and treatment modalities. On a molecular level, electrical remodeling lies on impaired calcium handling, enhanced inwardly rectifying potassium currents, and gap junction perturbations. In addition, a wide array of profibrotic stimuli activates fibroblast to an increased extracellular matrix turnover via various intermediaries. Concomitant dysregulation of the autonomic nervous system and the humoral function of increased epicardial adipose tissue (EAT) are established mediators in the pathophysiology of AF. Local atrial lymphomononuclear cells infiltrate and increased inflammasome activity accelerate and perpetuate arrhythmia substrate. Finally, impaired intracellular protein metabolism, excessive oxidative stress, and mitochondrial dysfunction deplete atrial cardiomyocyte ATP and promote arrhythmogenesis. These overlapping cellular and molecular alterations hinder us from distinguishing the cause from the effect in AF pathogenesis. Yet, a plethora of therapeutic modalities target these molecular perturbations and hold promise in combating the AF burden. Namely, atrial selective ion channel inhibitors, AF gene therapy, anti-fibrotic agents, AF drug repurposing, immunomodulators, and indirect cardiac neuromodulation are discussed here