Search results for "Metals"
showing 10 items of 2013 documents
Electrochemical synthesis of sulfamides.
2021
Herein we demonstrate the first electrochemical synthesis protocol of symmetrical sulfamides directly from anilines and SO2 mediated by iodide. Sulfamides are an emerging functional group in drug design. Highlights are the direct use of SO2 from a stock solution and no necessity of any supporting electrolyte. Overall, the reaction has been demonstrated for 15 examples with yields up to 93%.
Characterization of aquatic humic substances and their metal complexes by immobilized metal-chelate affinity chromatography on iron(III)-loaded ion e…
2001
The analytical fractionation of aquatic humic substances (HS) by means of immobilized metal-chelate affinity chromatography (IMAC) on metal-loaded chelating ion exchangers is described. The cellulose HYPHAN, loaded with different trivalent ions, and the chelate exchanger Chelex 100, loaded to 90% of its capacity with Fe(III), were used. The cellulose HYPHAN, loaded with 2% Fe(III), resulted in HS distribution coefficients Kd of up to 10(3.7) mL/g at pH 4.0 continuously decreasing down to 10(1.5) at pH 12, which were appropriate for HS fractionation by a pH-depending chromatographic procedure. Similar distribution coefficients Kd were obtained for HS sorption onto Fe(III)-loaded Chelex 100. …
Characterization of poly(N-alkylanilines) by Raman spectroscopy
2007
Abstract Thin films of poly( N -alkylaniline) were synthesized in acidic aqueous solution and in mixtures of aqueous and organic solvents. The polymer films (alkyl = methyl, ethyl, propyl and butyl) were characterized by Raman spectroscopy with the excitation wavelengths of 514.5, 632.8 and 780 nm. The main Raman bands have been characterized for the leucoemeraldine, emeraldine and pernigraniline oxidation states between −0.2 and 0.8 V (vs. Ag|AgCl). This fundamental study shows that the structure of the half-oxidized emeraldine form contains quinoid units, which supports the commonly accepted oxidation and reduction scheme of poly( N -alkylanilines).
Electropolymerization of N-methylanthranilic acid and spectroelectrochemical characterization of the formed film
2009
Abstract The electropolymerization of N-methylanthranilic acid (NMAA) is reported in this paper. The monomer is substituted both at ortho- and N-position and, to the best of our knowledge, it has not been previously electropolymerized. Electropolymerization of NMAA was done on glassy carbon and optically transparent (indium) tin oxide electrodes. The obtained films, which are probably of an oligomeric nature (oligoNMMA), were characterized with cyclic voltammetry (CV), in situ UV–vis and Raman spectroscopy, ex situ FTIR spectroscopy and scanning electron microscopy (SEM). Our results show that NMAA can be electropolymerized as thin films in 1.0 M HClO4, but the oxidation and reduction peak …
Optical planar Bragg grating sensor for real-time detection of benzene, toluene and xylene in solvent vapour
2012
Abstract We report on an optical planar Bragg grating sensor functionalized by a comparatively simple method to detect substances such as benzene, toluene and xylene (BTX). The functionalization is performed by allyl substituted γ -cyclodextrin derivatives which are immobilized on the sensor surface by dip coating. Our results prove the capability of this functionalized sensor system to detect lowest concentrations of BTX in solvent vapour in real-time with a sensitivity of 3±0.4 pm/100 ppm for benzene, 8±1 pm/100 ppm for toluene and 32±1 pm/100 ppm for m-xylene. Taking into account the spectral resolution and repeatability of the interrogation system this corresponds to a minimum concentra…
Quantum dot/cyclodextrin supramolecular systems based on efficient molecular recognition and their use for sensing.
2011
A supramolecular system based on ketoprofen functionalised CdSe/ZnS nanoparticles and pyrene-modified β-CD was prepared and successfully used for molecular sensing of different analytes. In addition, a strategy for the individual recovery of all the components of the sensing assay is reported.
In vitro evaluation of leishmanicidal properties of a new family of monodimensional coordination polymers based on diclofenac ligand
2020
Some series of isostructural chains with general formula [M(diclof)(HO)]·(EtOH) have been obtained from reaction between diclofenac ligand (diclof) and first row transition salts (M = Mn (1),Ni (2) and Co (3)). These monodimensional coordination polymers have been characterized and their crystal structures have been solved by X-ray diffraction methods, elucidating isostructural compounds that are chains with water molecules acting as bridge between different metallic centers, while diclofenac ligands are coordinated to the octahedral coordination environment of the same. Magnetic studies of these complexes have revealed the existence of moderate ferromagnetic interactions among manganese, n…
Study of the interaction of [Cu(bipy)]2+ with oxalate and squarate in aqueous solution
1988
A study of the formation of complexes between [Cu(bipy)]2+ and ox2− and sq2− in aqueous solution, (bipy being 2,2′-bipyridine and ox2− and sq2− the dianions of ethanedioic acid and 3,4-dihydroxy-3-cyclobutene-1,2-dione, respectively), has been carried out with the aim of comparing the coordinating properties of these related ligands. The constants of the equilibria (i) and (ii) $$[Cu(bipy)]^{2 + } + ox^{2 - } \rightleftharpoons [Cu(bipy)ox]$$ (i) $$[Cu(bipy)]^{2 + } + sq^{2 - } \rightleftharpoons [Cu(bipy)sq]$$ (ii) have been determined by potentiometry and spectrophotometry at 25.0°C and 0.1 M NaNO3:logβ=5.78(2) and 2.16(2) for the oxalato- and squarato-complex, respectively. Such differen…
The impact of Pleurotus ostreatus on organic matter transformation processes.
2012
This study showed the effect of Pleurotus ostreatus on the external organic matter (OM) transformation processes. The kinetics of these changes were determined. The experiment was conducted as 42-day pot experiment done in four combinations (with four replications). The four combinations of different substrates were: (1) organic, (2) composted hay, (3) organic soil + composted hay, (4) organic soil + composted hay + lead. The study results showed that P. ostreatus had the ability to transform external OM as well as metal–organic complexes. These transformations were reflected in the constant rate of characterized changes and correlation coefficients. The study also indicated the direction o…
Reversible stimulus-responsive Cu(i) iodide pyridine coordination polymer
2015
We present a structurally flexible copper–iodide–pyridine-based coordination polymer showing drastic variations in its electrical conductivity driven by temperature and sorption of acetic acid molecules. The dramatic effect on the electrical conductivity enables the fabrication of a simple and robust device for gas detection. X-ray diffraction studies and DFT calculations allow the rationalisation of these observations.