Ceric ammonium nitrate (CAN) as oxidizing or nitrating reagent for organic reactions in ionic liquids

The reaction of ceric ammonium nitrate, (NH₄)₂[Ce(NO₃)₆] or CAN, with naphthalene and 2-methylnaphthalene in the ionic liquid 1-ethyl-3-methylimidazolium triflate showed that the reaction products are strongly dependent on the water content of the ionic liquid and that cerium(IV) in the ionic liquid can electrochemically be regenerated.     

Study of Quantitative Structure-Retention Relationships for s-Triazine Derivatives in Different RP HPTLC Systems

JPC – Journal of Planar Chromatography – Modern TLC - Quantitative structure-retention relationships (QSRR) have been used to study the chromatographic behavior of some s-triazines....     

Application of multicomponent spectrophotometry in analysis of copper electroplating bath solutions

Multiwavelength multicomponent analysis for copper and nickel is explored within the spectral range 230-900 nm in order to enable copper (?0.2 g l^?1) and nickel to be determined simultaneously even at high (20 l^?1) and nickel concentrations in industrial electroplating baths. Calibration based on pure-component spectra is compared to multivariate calibration based on data reduction with principal component analysis with the partial least-square algorithm. By use of multivariate calibration techniques, sulphuric acid can also be determined indirectly by its effect on the absorbance of the metal ions. The performance of the method is evaluated for different spectral ranges and the experimental results are related to the selectivity of the different systems quantified by the condition number of the actual absorptivity matrix.     

Convex additively slowly varying functions

We study the problem of subtraction of slowly varying functions. It is well-known that the difference of two slowly varying functions need not be slowly varying and we look for some additional conditions which guarantee the slow variation of the difference. To this end we consider all possible decompositions L=F+G of a given increasing convex additively slowly varying function L into a sum of two increasing convex functions F and G. We characterize the class of functions L for which in every such decomposition the summands are necessarily additively slowly varying. The class OΠ₂⁺ we obtain is related to the well-known class OΠ_g where, instead of first order differences as in OΠ_g, we have second order differences.     

Kinetics of inhibition of peroxidase activity of myeloperoxidase by quercetin

The inhibition of myeloperoxidase (MPO), isolated from human neutrophils, by quercetin was investigated by following peroxidase activity of the enzyme using o-dianisidine as the substrate. The inhibition parameters (IC₅₀) were obtained by graphical analysis of the inhibition curves. A reaction mechanism, which involved the enzyme inhibition by quercetin and H₂O₂ in excess, was proposed. The rate and equilibrium constants for the proposed reaction path were calculated from experimental data. Kinetic analysis in noninhibiting H₂O₂ concentration range in the absence and the presence of quercetin revealed that the reaction mechanism underwent Michaelis–Menten kinetics. K and V values indicated that quercetin was a mixed inhibitor of MPO activity. The initial reaction rates were recalculated using the obtained results. Calculated curves fitted the experimental results within the range of experimental error. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 384–394, 2008     

Carboxyl-functionalized task-specific ionic liquids for solubilizing metal oxides

Imidazolium, pyridinium, pyrrolidinium, piperidinium, morpholinium, and quaternary ammonium bis(trifluoromethylsulfonyl)imide salts were functionalized with a carboxyl group. These ionic liquids are useful for the selective dissolution of metal oxides and hydroxides. Although these hydrophobic ionic liquids are immiscible with water at room temperature, several of them form a single phase with water at elevated temperatures. Phase separation occurs upon cooling. This thermomorphic behavior has been investigated by (1)H NMR, and it was found that it can be attributed to the temperature-dependent hydration and hydrogen-bond formation of the ionic liquid components. The crystal structures of four ionic liquids and five metal complexes have been determined.     

Synthesis,characterization of V2O5 nanoparticles and determination of catalase mimetic activity by new colorimetric method

Journal of Thermal Analysis and Calorimetry - This paper deals with an advanced colorimetric method used to determine the catalase mimetic activity of V2O5 nanoparticles by measuring the decrease...     

Highly Amino Acid Selective Hydrolysis of Myoglobin at Aspartate Residues as Promoted by Zirconium(IV)‐Substituted Polyoxometalates

SDS‐PAGE/Edman degradation and HPLC MS/MS showed that zirconium(IV)‐substituted Lindqvist‐, Keggin‐, and Wells–Dawson‐type polyoxometalates (POMs) selectively hydrolyze the protein myoglobin at Asp? X peptide bonds under mildly acidic and neutral conditions. This transformation is the first example of highly sequence selective protein hydrolysis by POMs, a novel class of protein‐hydrolyzing agents. The selectivity is directed by Asp residues located on the surface of the protein and is further assisted by electrostatic interactions between the negatively charged POMs and positively charged surface patches in the vicinity of the cleavage site.