Aurelia Visa

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. Graphical Abstract

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

BackgroundResearch 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 (Oh) network of cobalt vinylphosphonate (Co(vP)·H2O).ResultsA recurrent relationship of the ratio between the number of ligands and the number of metal ions in a lamellar octahedral (Oh) network Co(vP)·H2O, 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.ConclusionsBased 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 Oh coordinated and bring valuable information with low effort and cost.

Synthesis, characterizations and Pb(II) sorption properties of cobalt phosphonate materials

Abstract Due to the large amount of industrial activity during the last century, heavy metal contamination of the environment has become a serious problem. Therefore, it is important to develop new and efficient methods of heavy metals removal from aqueous solutions. In this respect, three phosphonate metal organic frameworks were obtained in our labs by the reaction of divalent inorganic salt (CoSO4·7H2O), phosphonic acid [phosphonoacetic (CP), N,N-bis(phosphonomethyl)glycine (Gly) and vinylphosphonic (VP)] in hydrothermal conditions. The synthesized compounds were characterized by FTIR, X-Ray crystallography scanning electron microscopy and thermogravimetric analysis. These materials were used in the removal process of lead ions from aqueous solutions in order to determine the possibilities of their use as adsorbent materials. The effect of pH, lead initial concentrations and contact time upon the adsorption properties were investigated. From the experimental data it can be observed that the Co-Gly material developed a higher adsorption capacity for lead metal ions than the Co-VP and Co-CP, increasing following Co-CP

Synthesis and Characterization of a Novel Phosphonate Metal Organic Framework Starting from Copper Salts

Abstract Increased interest in the area of metal phosphonate inorganic–organic frameworks is exemplified with a high range of applications and a rich synthetic and structural chemistry of these compounds. The synthesis and potential applications of a novel metal phosphonate, namely Cu(II) phenylvinylphosphonate (PVP) is described in this paper. Syntheses were performed starting from a 1:1 molar ratio of a Cu(NO3)2·6H2O or CuSO4·5H2O and 1-phenylvinylphosphonic acid under hydrothermal conditions at pH values ranging between 2.8 and 3.1. The influence of different counterion for the copper salt used as the Cu(II) source on the structure and crystallinity of the final product was studied. The obtained copper(II) phenylvinylphosphonate compounds were characterized by X-ray powder diffraction, FT-IR spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and energy-dispersive X-ray spectrometry (EDAX). A possible crystal structure for the copper (II) phenylvinylphosphonate products is proposed using semiempirical approaches. GRAPHICAL ABSTRACT

Promiscuous stabilisation behaviour of silicic acid by cationic macromolecules: the case of phosphonium-grafted dicationic ethylene oxide bolaamphiphiles{

Phosphonium-based bolaamphiphiles have been found to stabilise silicic acid beyond its solubility limit (∼150 ppm). Three bolaamphiphiles have been tested having a quaternary phosphonium group on each end, linked by a number of ethylene oxide (EO) units (5, 21, and 91, resulting in PEGP+-200, PEGP+-1000, and PEGP+-4000 dicationic bolaamphiphiles, respectively). Specifically, the ability of PEGP+-200, PEGP+-1000, and PEGP+-4000 to retard silicic acid condensation at circumneutral pH in aqueous supersaturated solutions was explored. The goal was to investigate the effect of P-based cationic molecules, EO chain length (and by inference the P-to-P spatial separation) on silicic acid stabilisation performance. PEGP+-200 showed no stabilisation ability in “long term” tests (i.e. 24, 48, 72 h). For PEGP+-1000, and PEGP+-4000, it was discovered that in “short-term” (0–8 h) and “long term” (> 24 h) studies the inhibitory activity is additive dosage-dependent, demonstrating that there is a clear increase in stabilisation ability upon phosphonium PEG dosage increase. Specifically, soluble silicic acid levels reach 420 ppm and 400 ppm after 24 h in the presence of 150 ppm PEGP+-1000, or PEGP+-4000, respectively. PEG additives (PEG-200, PEG-1000, and PEG-4000) containing no phosphonium cations were also tested. Although PEG-200 and PEG-1000 showed no silicic acid stabilisation effects, PEG-4000, surprisingly, was a strong stabiliser. In fact, the inhibitory efficiencies of PEGP+-4000 and PEG-4000 were virtually identical. These results present strong proof that the polyethylene chain beyond a certain length strongly contributes to silicic acid stabilisation. Lastly, the effects of these boloamphiphiles on silica particle morphology were investigated by SEM. Spherical particles and their aggregates, irregularly shaped particles and porous structures, are obtained depending on the additive.

Effect of a phosphonium salt grafted on polymers on cucumber germination and initial growth

The aims of this study were the synthesis, characterization and the testing of vinyldiphenylphosphonium salt phytotoxicity. Phytotoxicity of the synthesised salt was tested on Cucumis sativus L. seed germination and early seedling growth, at five different concentrations, using a standardized toxicity test. Endpoints included the determination of some seedling parameters: root and shoot length, root and shoot biomass, root and shoot dry weight ratio and final germination percentage. The vinyldiphenylphosphonium salt showed moderate to strong root length and root biomass inhibition, which increases progressively with the increasd of the concentration level.

Co-Vinyl Phosphonate Electrical Properties

GRAPHICAL ABSTRACT Abstract Starting from the X-ray experimental data of Co-vinyl phosphonate (VP-Co), a theoretical study was performed using quantum-chemical calculus with PM3 semiempirical method using Hyperchem 7

The Influence of pH on the Properties of Cobalt Styrylphosphonate

Abstract The synthesis of a new metal phosphonate and the influence of pH on its crystallinity is presented. Cobalt styrylphosphonate was synthesized by 2 methods (75°C, 180°C) at pH 1.5, 2, 2.4, 2.8, and 3.2, and its crystallinity was confirmed by X-ray powder diffraction. GRAPHICAL ABSTRACT

EQUILIBRIUM AND KINETIC STUDIES OF CHROMIUM IONS ADSORPTION ON Co(II) BASED PHOSPHONATE METAL ORGANIC FRAMEWORKS

ABSTRACT Chromium is present in wastewaters resulted from a lot of industrial processes such as electroplating, dye, cement, leather tanning, and paint. Its presence at values higher than maximum admitted value of 0.05 mg/L can affect the human health and the environment. Therefore, it is essential to remove chromium from wastewaters before discharge. In this study, the adsorption potential of three types of Co (II)-based phosphonate metal organic frameworks, obtained by the reaction of CoSO4.7H2O with phosphonoacetic acid (CP), N,N-bis(phosphonomethyl)glycine (Gly), or vinyl phosphonic acid (VP) in hydrothermal conditions, has been investigated. The study involves batch types experiments investigating the effects of the solution pH, solid:liquid ratio, initial concentration of Cr(VI), and contact time upon the adsorption efficiency of the studied materials. Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich were applied to adsorption equilibrium data to find the best among these models. The kinetics of adsorption was found to follow the pseudo-second-order model. It was found that the adsorption efficiency of the studied materials in the removal process of Cr(VI) ions from aqueous solutions is in the following order: Co-CP

Hypophosphorous Acid and Its Salts as Reagents in Organophosphorus Chemistry

In the last decades, the interest in the organophosphorus compound preparation using chlorine-free reagents has been of great importance, due to significant applications of phosphorus compounds as reagents in future synthesis. Usually, organophosphorus derivatives are obtained starting from phosphorus trichloride or phosphoryl chloride, although the final products do not have reactive phosphorus–chlorine bonds. In the last period the interest is to replace the halogen-containing compounds with other starting reagents using environmentally safe paths. In this chapter we tried to summarize the aspects of using hypophosphorous acid and its salts as reagents for organophosphorus compounds. The chapter is focused on the synthesis of α-aminophosphinic acid, α-aminophosphinates, H-phosphinic acids, and H-phosphinates. These reactions are discussed in classical conditions and, as microwave-assisted synthesis, in the presence or absence of metal catalysts or reaction solvents. Phosphonate metal organic frameworks are an important class of materials, which achieves dramatic growth in the last 15 years. Therefore a brief overview of the reactivity of phosphinic acids used to obtain phosphonic acids is provided.