Phenanthroline-based Ni(II) coordination compounds involving unconventional discrete fumarate-water-nitrate clusters and energetically significant cooperative ternary π-stacked assemblies: Antiproliferative evaluation and theoretical studies

This study investigated the protective effect of experimental solutions containing 4 polymers (polyoxirane, hydroxypropylmethylcellulose [HPMC], pectin, and an amino methacrylate copolymer [AMC]) in 2 concentrations (low and high) associated or not with sodium fluoride (F; 225 ppm F-) or sodium fluoride plus stannous chloride (FS; 800 ppm Sn2+) on the dissolution of hydroxyapatite crystals (HA). Deionized water was the control. The pretreated HA was added to a 0.3% citric acid solution (pH 3.8). An automatic titrant machine added aliquots of 0.1 N HCl at a rate of 28 μL/min, in a total reaction time of 5 min. Groups were compared with 2-way ANOVA and Tukey's test, and concentrations with Student t test (5%). The zeta potential of the HA treated with the solutions was measured. Significant differences were found for both factors and interaction (p < 0.0001). The treatments with F and FS solutions resulted in a lower amount of dissolved HA than the control. Among the polymers' solutions, only AMC was able to reduce the amount of dissolved HA, changing the surface charge of HA to positive. AMC improved the protective effect of F, but it did not affect FS. Polyoxirane and HPMC reduced the protective potential of the FS solution. No differences were found between the concentrations of the polymers. It was concluded that F and FS reduced the amount of dissolved HA. The protective effect of the experimental solutions against HA dissolution was polymer dependent. The F effect was enhanced by its combination with AMC, but the protection of FS was impaired by polyoxirane and HPMC.

Protective Effect of Solutions Containing Polymers Associated with Fluoride and Stannous Chloride on Hydroxyapatite Dissolution.

This research focuses on a novel visible light-responsive photocatalysis system employing MoS2 and magnetically responsive BiFeO3 for removing dye. Novel BiFeO3/MoS2 magnetic nanocomposite was succ...

Construction of novel magnetic BiFeO3/MoS2 composite for enhanced visible-light photocatalytic performance towards purification of dye pollutants

The fluorination efficiency of a fluorinating agent depends on the free availability of the fluoride ions, which in turn depends on its interaction with its solvation shell. A stable fluoride-based poor solvate ionic liquid (SIL) comprising 1-ethyl-3-methylimidazolium (EMIM) cation and ethylene glycol (EG) was recently reported and demonstrated as a fluorinating agent. Herein, we performed ab initio calculations and ab initio molecular dynamics simulations to gain a microscopic understanding of the intermolecular interactions in this SIL in gas, liquid, and crystalline phases. Ethylene glycol (EG), being capable of forming hydrogen bond(s) with the fluoride ion, prevents the latter from reacting with the EMIM cation. Fluoride forms hydrogen bonds with both the cation and the EG molecule, but it was found to have more affinity toward EG, forming a stronger hydrogen bond with its hydroxyl proton than with the acidic proton of the cation. An optimal concentration of EG in the SIL balances its contribution to stabilizing the fluoride ion and yet making fluoride available for fluorination.

Insights into the Stabilization of Fluoride Ions in Ionic Liquids: Pointers to Better Fluorinating Agents.

Three crystalline complexes containing fluorine anion water clusters, [Cd(Im)6][F·H2O]2 (1), [Ni(Im)6][F2·(H2O)5] (2) and [Co(Im)6][F·NO3·(H2O)4] (3), were reported. The interesting fluorine anion water clusters are described in this paper. Single X-ray analysis shows that fluoride ions in the water clusters have different coordination environments, four-coordinated in a tetrahedral geometry for (1), five-coordinated in a trigonal bipyramidal geometry for (2), and three-coordinated in a planar trigonal geometry for (3). F−(H2O)n is assembled by strong H-bonding interactions [OH⋯F = 2.576(1)–2.813(1) A], where a fluoride anion plays an important role in connecting an imidazole ligand of the host [M(Im)6]2+. The strength of an ionic bond between the host and guest is strongly influenced by the F−(H2O)n water cluster adjacent to the ligand with NH⋯F distances of 2.607–2.755 A. The TGA, IR and XRD studies for the above three compounds at different testing temperatures suggested that the fluorine anion water cluster, F−(H2O)n, was very stable. This result distinctly differentiates these compounds from the reported ones containing neutral water cluster molecules. This phenomenon indicated the stronger anionic hydrogen-bond interaction between F− and H2O, which also confirmed the intracluster proton transfer process F−·H2O → HF·OH−. This result suggests that the fluorine anions and water molecules are H-bonded to each other in an alternating fashion within the fluoride−water hybrid cluster, where a fluorine anion plays the important role of connecting the host metal complex and guest water cluster.

Jun Ying Ma

Papers

Interesting fluorine anion water clusters [F−·(H2O)n] in metal complex crystals