Structure simulation into a lamellar supramolecular network and calculation of the metal ions/ligands ratio

BACKGROUND: Research interest in phosphonates metal organic frameworks (MOF) has increased extremely in the last two decades, because of theirs fascinating and complex topology and structural flexibility. In this paper we present a mathematical model for ligand/metal ion ratio of an octahedral (O(h)) network of cobalt vinylphosphonate (Co(vP)·H(2)O). RESULTS: A recurrent relationship of the ratio between the number of ligands and the number of metal ions in a lamellar octahedral (O(h)) network Co(vP)·H(2)O, has been deducted by building the 3D network step by step using HyperChem 7.52 package. The mathematical relationship has been validated using X ray analysis, experimental thermogravimetric and elemental analysis data. CONCLUSIONS: Based on deducted recurrence relationship, we can conclude prior to perform X ray analysis, that in the case of a thermogravimetric analysis pointing a ratio between the number of metal ions and ligands number around 1, the 3D network will have a central metal ion that corresponds to a single ligand. This relation is valid for every type of supramolecular network with divalent metal central ion O(h) coordinated and bring valuable information with low effort and cost

Unsaturated phosphonic acid, a novel precursor to fabricate metal organic frameworks

Investigations on phosphonates metal organic frameworks (MOFs) have attracted interest during the last two decades due to their captivating network topology, structural flexibility and multiple special properties. The synthesis of 1 -phenylphosphonium acid, as precursor of metal organic framework was described. The synthesized compound was analyzed by 'H and 31P-NMR, HPLC, MS, TG and IR spectroscopy. The PM3 semi-empirical analysis of precursor was made in order to establish their design, structural properties, thermodynamic and electronic properties

Synthesis and characterization of a new metal organic framework

The synthesis of a new metal-phosphonate is described in this paper. Mg2+ vinylphosphonate has been synthesized by using an equimolecular ratio of reagents in hydrothermal conditions. The compound has been characterized by X-Ray and IR spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), thermo gravimetry (TG) and quantum chemical calculations. Last method have been used to establish supramolecular pores size and to predict synthesized compound ability to filter hydrogen, methane, carbon dioxide, carbon monoxide, sulphur dioxide and benzene gases

Synthesis and structural characterization of 2-D layered copper(II) styrylphosphonate coordination polymers

We report the synthesis, physicochemical characterization, and crystal structure of Cu-SP (SP = styrylphosphonic acid, H2O3PCH=CH2(C6H5)), the first reported example of a metal derivative of SP. The starting SP acid was fully characterized by X-ray single-crystal diffractometry, elemental analysis (C and H), 31P-NMR, 13C-NMR, 1H-NMR, HPLC, UV–vis, MS, TG, and FT-IR spectroscopy. The copper(II) derivative was synthesized and characterized by DTA-TG and FT-IR, and also its structure was determined from powder data. The crystal structure was refined by the Rietveld method. The crystal structure of Cu-SP shows a layered 2-D architecture, where the organic moieties are pointed toward the interlamellar space. The inorganic layers are composed of Cu2+ dimers, where the coordination geometry of Cu2+ can be described as distorted trigonal bipyramid. The three coplanar oxygens (O2, O3, and O3) have bond distances of 2.165(9), 1.982(9), and 2.103(11) Å, respectively. The bond lengths for the apical oxygens (O1 and O2) are 1.908(13) and 1.996(11) Å, respectively.Proyecto nacional MAT2010-1517

Synthesis and Electrochemical properties of metal(II)- carboxyethylphenylphosphinates

https://doi.org/10.1039/D1DT00104CWe report herein the synthesis, structural characterization and electrocatalytic properties of three new coordination polymers, resulting from the combination of divalent metal (Ca2+, Cd2+ or Co2+) salts with (2-carboxyethyl)(phenyl)phosphinic acid. In addition to the usual hydrothermal procedure, the Co2+ derivative could be also prepared by microwave-assisted synthesis, in much shorter times. The crystal structures were solved ab initio, from powder diffraction data. Compounds MII[O2P(CH2CH2COOH)(C6H5)]2 {M= Cd (1) or Ca (2)} crystallize in the monoclinic system and display a layered topology, with the phenyl groups pointing toward the interlayer space in a interdigitated fashion. Compound Co2[(O2P(CH2CH2COO)(C6H5)(H2O)]2·2H2O (3) presents a 1D structure composed of zig-zag chains, formed by edge-sharing cobalt octahedra, with phenyl groups pointing outside. Packing of these chains is favored by hydrogen bond interactions via lattice water. In addition, H-bonds along the chains are established with participation of the water molecules and the hydrophilic groups from the ligand. However, the solid exhibits a low proton conductivity, attributed to the isolation of the hydrophilic regions caused by the arrangement of hydrophobic phenyl groups. Preliminary studies on the electrocatalytical performance for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) have been conducted for compound 3 and its pyrolytic derivatives, which were previously throughout characterized. By comparison, another Co2+ phosphinate, 4, obtained by microwave-assisted synthesis, but with distinct stoichiometry and known structure was also tested. For OER, the best performance was reached with a derivative of 3, prepared by heating this compound in N2 at 200 °C. This derivative presented overpotential (339 mV, for a current density of 10 mA·cm-2) and Tafel slope (51.7 mV·dec-1) values comparable to other Co2+ related materials.Proyecto nacional del MICINN MAT2016-77648-R; PID2019-110249RB-I00 y FQM-113 proyectos de la Junta de Andalucía. Plan Propio de la UMA y ALBA Sincrotrón por la utilización de la línea BM04 beam-line en el experimento (proposal nº 2016091873

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

Applications of Metal-Organic Frameworks as Drug Delivery Systems

In the last decade, metal organic frameworks (MOFs) have shown great prospective as new drug delivery systems (DDSs) due to their unique properties: these materials exhibit fascinating architectures, surfaces, composition, and a rich chemistry of these compounds. The DSSs allow the release of the active pharmaceutical ingredient to accomplish a desired therapeutic response. Over the past few decades, there has been exponential growth of many new classes of coordination polymers, and MOFs have gained popularity over other identified systems due to their higher biocompatibility and versatile loading capabilities. This review presents and assesses the most recent research, findings, and challenges associated with the use of MOFs as DDSs. Among the most commonly used MOFs for investigated-purpose MOFs, coordination polymers and metal complexes based on synthetic and natural polymers, are well known. Specific attention is given to the stimuli- and multistimuli-responsive MOFs-based DDSs. Of great interest in the COVID-19 pandemic is the use of MOFs for combination therapy and multimodal systems

Applications of Metal-Organic Frameworks as Drug Delivery Systems

In the last decade, metal organic frameworks (MOFs) have shown great prospective as new drug delivery systems (DDSs) due to their unique properties: these materials exhibit fascinating architectures, surfaces, composition, and a rich chemistry of these compounds. The DSSs allow the release of the active pharmaceutical ingredient to accomplish a desired therapeutic response. Over the past few decades, there has been exponential growth of many new classes of coordination polymers, and MOFs have gained popularity over other identified systems due to their higher biocompatibility and versatile loading capabilities. This review presents and assesses the most recent research, findings, and challenges associated with the use of MOFs as DDSs. Among the most commonly used MOFs for investigated-purpose MOFs, coordination polymers and metal complexes based on synthetic and natural polymers, are well known. Specific attention is given to the stimuli- and multistimuli-responsive MOFs-based DDSs. Of great interest in the COVID-19 pandemic is the use of MOFs for combination therapy and multimodal systems

Chemical Modification of Chitosan for Removal of Pb(II) Ions from Aqueous Solutions

Biomacromolecule have a significant contribution to the adsorption of metal ions. Moreover, chitosan is one of the most studied biomacromolecule, which has shown a good performance in the field of wastewater treatment. In this context, a new adsorbent of the aminophosphonic modified chitosan-supported Ni(II) ions type was prepared from the naturally biopolymer, chitosan. In the first step, modified chitosan with aminophosphonic acid groups was prepared using the “one-pot” Kabachnik-Fields reaction. It was characterized by different techniques: FTIR, SEM/EDAX, TGA, and 31P-NMR. In the second step, the modified chitosan with aminophosphonic acid was impregnated with Ni(II) ions using the hydrothermal reaction at different values of pH (5, 6 and 7). The physical-chemical characteristics of final products (modified chitosan carrying aminophosphonic groups and Ni(II) ions) were investigated using FTIR, SEM images, EDAX spectra and thermogravimetric analysis. In this work, the most important objective was the investigation of the adsorbent performance of the chitosan modified with aminophosphonic groups and Ni(II) ions in the process of removing Pb(II) ions from aqueous solutions by studying the effect of pH, contact time, and Pb(II) ions concentration. For removal of Pb(II) ions from the aqueous solution, the batch adsorption method was used