Search results for "polymeerit"
showing 10 items of 34 documents
Construction of Coordination Polymers from Semirigid Ditopic 2,2′-Biimidazole Derivatives: Synthesis, Crystal Structures, and Characterization
2017
Eight coordination polymers (CPs), {[Ag(L1)]ClO4}n (1), {[Ag(L2)1.5]ClO4·C2H3N}n (2a), {[Ag(L2)]ClO4}n (2b), [Zn(L1)Cl2]n (3), {[Zn(L2)Cl2]·CHCl3}n (4), {[Cu(L1)2Cl]Cl·H2O}n (5), [Cu2(L2)(μ-Cl)2]n (6), and [Cu4(L2)(μ-Cl)4]n (7) were synthesized via self-assembly of corresponding metal ions and biimidazole based ditopic ligands, 1,1′-bis(pyridin-3-ylmethyl)-2,2′-biimidazole L1 and 1,1′-bis(pyridin-4-ylmethyl)-2,2′-biimidazole L2. These ligands possess conformational flexibility and two pairs of coordination sites: pyridine nitrogen (NPy) atoms and imidazole nitrogen (NIm) atoms. Depending on the metal center in CPs, the biimidazole compounds act as tetra- (1, 7), tri- (2a), or bidentate (2a,…
Iron-based metal-organic framework: Synthesis, structure and current technologies for water reclamation with deep insight into framework integrity.
2021
Water is a supreme requirement for the existence of life, the contamination from the point and non-point sources are creating a great threat to the water ecosystem. Advance tools and techniques are required to restore the water quality and metal-organic framework (MOFs) with a tunable porous structure, striking physical and chemical properties are an excellent candidate for it. Fe-based MOFs, which developed rapidly in recent years, are foreseen as most promising to overcome the disadvantages of traditional water depolluting practices. Fe-MOFs with low toxicity and preferable stability possess excellent performance potential for almost all water remedying techniques in contrast to other MOF…
Highly selective recovery of Ni(II) in neutral and acidic media using a novel Ni(II)-ion imprinted polymer
2022
In this work, an original ion-imprinted polymer (IIP) was synthetized for the highly selective removal of Ni(II) ions in neutral and acidic media. First a novel functional monomer (AMP-MMA) was synthetized through the amidation of 2-(aminomethyl)pyridine (AMP) with methacryloylchloride. Following Ni(II)/AMP-MMA complex formation study, the Ni(II)-IIP was produced via inverse suspension polymerization (DMSO in mineral oil) and characterized with solid state 13C CPMAS NMR, FT-IR, SEM and nitrogen adsorption/desorption experiments. The Ni(II)-IIP was then used in solid-phase extraction of Ni(II) exploring a wide range of pH (from neutral to strongly acidic solution), several initial concentrat…
In-depth structural analysis of lanthanoid coordination networks based on a flexible tripodal zwitterionic isonicotinate ligand
2019
Crystallizing metal–organic frameworks (MOFs) has been studied using a tripodal pyridinecarboxylic acid derivative ligand and selected lanthanoid salts. The zwitterionic ligand, 1,1′,1′′-((2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene))tris(pyridin-1-ium-4-carboxylate) (TTTPC) introduced as a bromide salt, forms coordination networks in aqueous environments and under ambient conditions with neodymium bromide, trifluoromethanesulfonate (OTf) or acetate (OAc). Seven structures are elucidated in detail using single crystal X-ray crystallography. TTTPC NdBr3, TTTPC NdBr2OTf, TTTPC NdBr(OTf)2 and TTTPC Nd(OTf)3 are porous 3D networks with similar ligand–metal and ligand–anion interactions, b…
A novel 2D coordination network built from hexacopper(i)-iodide clusters and cagelike aminophosphine blocks for reversible “turn-on” sensing of anili…
2018
A new copper(I) coordination polymer [Cu6(μ3-I)6(μ3-PTAO)2]n (1) was prepared from copper(I) iodide and 1,3,5-triaza-7-phosphaadamantane-7-oxide (PTAO). The crystal structure of 1 reveals an intricate 2D coordination network constructed from the hexacopper(I)-iodide [Cu6(μ3-I)6] cluster units with the 4M6-1 topology interlinked by the μ3-PTAO spacers. An overall 2D layer network can be simplified to a binodal 3,6-connected net with the kgd topology. A derived 1@paper material was prepared by impregnating compound 1 onto a filter paper. Detailed investigation of the luminescence properties for 1 and 1@paper in the solid state revealed a remarkable ability of both materials to sense aniline m…
Alkali-Activated Adsorbents from Slags: Column Adsorption and Regeneration Study for Nickel(II) Removal
2021
Alkali-activated adsorbents were synthesized by mixing three different slags from the steel industry: blast furnace slag (BFS), ladle slag (LS), and Lintz–Donawitz converter slag (LD). These powdered slag-based geopolymers (GP) were used to remove nickel(II) from aqueous solutions in fixed-bed column studies. The experiments were conducted in pH 6 using a phosphate buffer with initial nickel(II) concentration of 50 mg/L. Samples were taken at time intervals of between 5 and 90 min. Three adsorption–desorption cycles were implemented with a flow rate of 5 mL/min. The geopolymers were characterized by Fourier-Transform Infrared Spectroscopy (FTIR), X-ray powder diffraction (XRD), Field Emissi…
Phased laser diode array permits selective excitation of ultrasonic guided waves in coated bone-mimicking tubes
2017
This paper validates simulation predictions, which state that specific modes could be enhanced in quantitative ultrasonic bone testing. Tunable selection of ultrasonic guided wave excitation is useful in non-destructive testing since it permits the mediation of energy into diagnostically useful modes while reducing the energy mediated into disturbing contributions. For instance, it is often challenging to distinguish and extract the useful modes from ultrasound signals measured in bone covered by a soft tissue. We show that a laser diode array can selectively excite ultrasound in bone mimicking phantoms. A fiber-coupled diode array (4 elements) illuminated two solid tubes (2-3mm wall thickn…
Organic Polyradicals as Redox Mediators: Effect of Intramolecular Radical Interactions on Their Efficiency
2020
The spin–spin interactions between unpaired electrons in organic (poly)radicals, especially nitroxides, are largely investigated and are of crucial importance for their applications in areas such as organic magnetism, molecular charge transfer, or multiple spin labeling in structural biology. Recently, 2,2,6,6-tetramethylpiperidinyloxyl and polymers functionalized with nitroxides have been described as successful redox mediators in several electrochemical applications; however, the study of spin–spin interaction effect in such an area is absent. This communication reports the preparation of a novel family of discrete polynitroxide molecules, with the same number of radical units but differe…
Reactive Self-Assembly and Specific Cellular Delivery of NCO-sP(EO-stat-PO)-Derived Nanogels
2018
This study presents the reactive self-assembly of isocyanate functional and amphiphilic six-arm, star-shaped polyether prepolymers in water into nanogels. Intrinsic molecular amphiphilicity, mainly driven by the isophorone moiety at the distal endings of the star-shaped molecules, allows for the preparation of spherical particles with an adjustable size of 100-200 nm by self-assembly and subsequent covalent cross-linking without the need for organic solvents or surfactants. Covalent attachment of a fluorescence dye and either the cell-penetrating TAT peptide or a random control peptide sequence shows that only TAT-labeled nanogels are internalized by HeLa cells. The nanogels thus specifical…
Infinite coordination polymer networks metallogelation of aminopyridine conjugates and in situ silver nanoparticle formation
2018
Herein we report silver(i) directed infinite coordination polymer network (ICPN) induced self-assembly of low molecular weight organic ligands leading to metallogelation. Structurally simple ligands are derived from 3-aminopyridine and 4-aminopyridine conjugates which are composed of either pyridine or 2,2'-bipyridine cores. The cation specific gelation was found to be independent of the counter anion, leading to highly entangled fibrillar networks facilitating the immobilization of solvent molecules. Rheological studies revealed that the elastic storage modulus (G') of a given gelator molecule is counter anion dependent. The metallogels derived from ligands containing a bipyridine core dis…