Search results for "ionic"
showing 10 items of 2016 documents
Development of competitive enzyme-linked immunosorbent assays for boscalid determination in fruit juices
2012
Abstract Boscalid is a modern, broad-spectrum carboxamide pesticide highly efficient against most fungal diseases affecting valuable crops. In this study, a boscalid-mimicking derivative with a six-carbon spacer arm replacing the chlorine atom at the pyridine ring of the target molecule was synthesized and coupled to carrier proteins. Following rabbit immunization, antibodies against this agrochemical were obtained for the first time, and they were characterised in terms of affinity and specificity, tolerance to solvents, and robustness to changes in buffer pH and ionic strength, using two assay formats. Both of the optimised immunoassays showed limits of detection below 0.1 μg/L. Moreover,…
Cations mobility and water adsorption in zeolites
2002
As already pointed out [1], dielectric relaxation spectroscopy can be a convenient tool for probing ion dynamic in solids which depends on i) the structure in which ions are embedded and ii) the nature of the interaction ion/network. Consequently, the results obtained from this technique can be used as a data base for theoretical studies which goal is to calculate the ion binding energy and to simulate ionic displacements. Inversely, theoretical calculations are essential for confirming the experimental data and more particularly the method which is used for analysing the dielectric experimental response.
Morphology of 1-alkyl-3-methylimidazolium hexafluorophosphate room temperature ionic liquids
2008
The structural organization in selected room temperature ionic liquids, namely (a) butyl-, (b) hexyl- and (c) octyl-3-methylimidazolium hexafluorophosphate, is investigated by means of X-ray diffraction. We find novel experimental evidences of the existence of a high degree of intermediate range order that is associated to nanoscale segregation of the alkyl chains into the charged matrix. The size of these structural heterogeneities depends linearly from the alkyl chain length. A similar behaviour had been observed in other systems, such as normal alcohols. The slope of such dependence provides hints on the nature of the structural organization of these segregated domains.
Tin compounds interaction with membranes of egg lecithin liposomes.
2007
This work is a continuation of earlier research concerning the influence of tin compounds on the dynamic properties of liposome membranes produced with lecithin hen egg yolks (EYL). The experiments were carried out at room temperature (about 25 ∞C). Four tin compounds were chosen, including three organic ones, (CH3)4Sn, (C2H5)4Sn and (C3H7)3SnCl, and one inorganic, SnCl2. The investigated compounds were admixed to water dispersions of liposomes. The content of the admixture changed within the range 0 mol-% to 11mol-% in proportion to EYL. Two spin probes were used in the experiment: 2,2,6,6-tetramethylpiperidine- 1-oxyl (TEMPO) and 2-ethyl-2-(15-methoxy-15-oxopentadecyl)-4,4-dimethyl-3-oxaz…
A new C–C bond formation model based on the quantum chemical topology of electron density
2014
ELF topological analyses of bonding changes in non-polar, polar and ionic organic reactions involving the participation of CC(X) double bonds make it possible to establish a unified model for C–C bond formation. This model is characterised by a C-to-C coupling of two pseudoradical centers generated at the most significant atoms of the reacting molecules. The global electron density transfer process that takes place along polar and ionic reactions favours the creation of these pseudoradical centers at the most nucleophilic/electrophilic centers of the reacting molecules, decreasing activation energies. The proposed reactivity model based on the topological analysis of the changes in electron…
ChemInform Abstract: A New C-C Bond Formation Model Based on the Quantum Chemical Topology of Electron Density
2014
ELF topological analyses of bonding changes in non-polar, polar and ionic organic reactions involving the participation of CC(X) double bonds make it possible to establish a unified model for C–C bond formation. This model is characterised by a C-to-C coupling of two pseudoradical centers generated at the most significant atoms of the reacting molecules. The global electron density transfer process that takes place along polar and ionic reactions favours the creation of these pseudoradical centers at the most nucleophilic/electrophilic centers of the reacting molecules, decreasing activation energies. The proposed reactivity model based on the topological analysis of the changes in electron…
Blockcopolymere aus 2-Isopropenylnaphthalin und Hexamethylcyclotrisiloxan, 7
1985
Anionic polymerization of 2-isopropenylnaphthalene (2-IPN), with butyllithium in THF at −78°C was terminated with ethylene oxide and the resulting terminal alkoxide was used to initiate the polymerization of hexamethylcyclotrisiloxane (D3) at +40°C. This led to the formation of AB-block copolymers which were coupled to ABBA-block copolymers by addition of dichlorodimethylsilane. ABBA-blockcopolymers were obtained with contents of polymethylsiloxane (poly(DMS)) between 77 and 84% of weight and block molecular weights between 1 700 and 27 000 (poly(2-IPN)) and 13 000 and 240 000 (poly(DMS)). Phase separation in polymer films casted from different solvents was studied by electron microscopy an…
Characterization of interaction between tricyclic structures containing pharmaceuticals, their models and humic substances.
2011
Their persistence and wide consumption identify pharmaceuticals as “emerging pollutants”. The complexation of pharmaceuticals containing adamantine ring structures and their model substances with humic acids (HA) of different origins was compared using fluorescence spectroscopy as a function of pH, humic acid concentration, ionic strength, and molecular mass of HA. Binding constants between the studied pharmaceuticals and humic acids were calculated. A combination of dynamic and static quenching processes as indicated by nonlinear Stern-Volmer plots and high Kd values were positively correlated with the concentration of carboxyl groups in the studied humic acids. For basic functional group-…
Biphasic ethylene polymerisation using ionic liquid over a titanocene catalyst activated by an alkyl aluminium compound
2007
Abstract 1-n-Butyl-3-methylimidazolium tetrachloroaluminate ([BMIM]+[AlCl4]−) was applied to biphasic ionic liquid/hexane ethylene polymerisation as a medium of the Cp2TiCl2 titanocene catalyst activated by alkylaluminium compounds (MAO, AlEt2Cl, AlEt3). The best results were obtained using AlEt2Cl. The results show that catalyst recycling, higher ethylene pressure, and greater Al/Ti molar ratio along with a greater volume of the ionic liquid phase enhance catalyst activity. The polyethylene gathered from the hexane phase is characterised primarily by its high purity. Its physical properties remain polyethylene obtained over a heterogeneous metallocene catalyst. Thus, biphasic ionic liquid …
DFT study of the interaction free energy of p–p complexes of fullerenes with buckybowls and viologen dimers
2011
We present a theoretical investigation, by means of DFT protocols, of the complexation thermodynamics of (i) complexes of C70 and C60 fullerenes with bowl-shaped hexabenzocoronene derivatives and (ii) complexes of C60 with viologen dimers. The recent functionals of the M06 family, accounting for p-p interactions to a good level of approximation, have been used to calculate the interaction free energies. For the former complexes, the good agreement between the calculated results and the experimental data confirms the reliability of the protocol used. On these grounds, we then checked the stability of a series of complexes of C60 with some viologen dimers, 1BPnBP1 (n = 6-9), where two N-methy…