Studies on the Phenol Oxidation by H2O2 Catalyzed by Metallomicelle Made from Crowned Schiff Base Co(II) Complexes Containing Benzoaza-15-crown-5

Three novel cobalt(II) complexes of the benzoaza-15-crown-5 Schiff base, CoL¹, CoL², and CoL³ were synthesized and characterized. Metallomicelles made from CoL and surfactants (CTAB, LSS, and Brij35) were used as mimetic peroxidase in the catalytic oxidation of phenol by H₂O₂. For comparison, the catalytic activity of the complexes (CoL¹, CoL², and CoL³) were also investigated. The mechanism and a kinetic mathematic model of the phenol catalytic oxidation were studied. The acid effect of reaction system, structural effect of the complexes, and effect of temperature on the rate of the phenol catalytic oxidation by the mimetic peroxidase were discussed. The results show that the Schiff base cobalt(II) complexes and their metallomicelles as peroxidase mimics exhibit good catalytic activity and similar catalytic character to natural enzyme.     

A New Two-dimensional Coordination Polymer Based on Trinuclear Manganese Clusters

A novel two-dimensional Mn（II） coordination polymer, [Mn3（L）R（cis-chdc）fftrans- chdc）]n （L = 2-amino-4-（1H-imidazo[4,5-J][1,10]phenanthrolin-2-yl）phenol and chdc = 1,4-cyclo- hexanedicarboxylate）, has been hydrothermally synthesized and characterized by elemental analysis, IR, TG PL and single-crystal X-ray diffraction. Crystallographic data for this compound： monoclinic space group P2/n with a = 11.0058（13）, b = 9.0179（11）, c = 28.431（3） A, β = 92.850（2）°, V = 2818.3（6） A3, Z = 2, C62Hs6Mn3N10O14, Mr = 1329.99, Dc = 1.567 g/cm3, F（000） = 1370, p（MoKa） = 0.742 mm-1, R = 0.0553 and wR = 0.1421. The chdc carboxylates bridge the Mn（II） atoms to form a trinuclear Mn（lI） cluster. The cis-chdc ligands are held together by the trinuclear Mn（II） clusters to result in a chain structure. Further, the trans-chdc ligands link adjacent chains to furnish a two-dimensional network. The π-π interactions between neighboring layers link the adjacent layers into a three-dimensional supramolecular architecture. Moreover, the N-H...O and O-H...O hydrogen bonds further stabilize the 3D supramolecular architecture.     

CONVERSION OF IN SITU GENERATED STABILIZED PHOSPHORUS YLIDES TO CHROMENE DERIVATIVES IN SOLVENT-FREE CONDITIONS

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by phenols (1-hydroxynaphthalene, 2-hydroxynaphthalene, 4-bromophenol, 2-hydroxybenzaldehyde, and 5-bromo-2-hydroxyben- zaldehyde) leads to vinyltriphenylphosphonium salts, which undergo electrophilic substitution reaction with conjugate base to produce corresponding stabilized phosphorus ylides. Microwave was found to catalyze conversion of the stabilized phosphorus ylides to chromene derivatives in the presence of solid catalysts in solvent-free conditions at microwave power 0.4 KW in 3 min.     

K2FeO4的合成及对含苯酚水溶液中重金属离子的去除性能

以次氯酸钙和九水硝酸铁为原料采用湿化学法合成K₂FeO₄,X射线衍射（XRD）、扫描电子显微镜（SEM）、红外吸收光谱（FTIR）、能量色散谱（EDS）的对比分析表明通过二次重结晶纯化可有效去除粗产品中的杂质,获得纯度更高、晶形更完整的K₂FeO₄晶体。同时研究了K₂FeO₄投加量、时间、溶液pH值、温度、初始离子浓度等因素下,K₂FeO₄对含苯酚水溶液中的Cu（Ⅱ）、Cd（Ⅱ）的去除性能,并通过扫描电子显微分析（SEM）、能量色散谱（EDS）、红外吸收光谱（FTIR）等方法研究了K₂FeO₄对溶液中重金属离子的去除机理。实验结果表明：K₂FeO₄可通过一步反应同时去除溶液中的Cu（Ⅱ）、Cd（Ⅱ）以及苯酚,K₂FeO₄主要通过吸附、共沉淀和表面配位的方式去除溶液中的重金属离子。     

MICROWAVE INDUCED SYNTHESIS OF COUMARINS FROM IN SITU GENERATED STABILIZED PHOSPHORUS YLIDES IN THE PRESENCE OF SILICA GEL POWDER IN SOLVENT-FREE CONDITIONS

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by phenols (1-hydroxynaphthalene, 2-hydroxynaphthalene and 4-bromophenol) leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with conjugate base to produce corresponding stabilized phosphorus ylides. Microwave was found to catalyze conversion of the stabilized phosphorus ylides to corresponding coumarins in the presence of silica gel powder in solvent-free conditions.     

Zeolite H‐Y–Supported Copper(II) Nitrate: A Simple and Effective Solid‐Supported Reagent for Nitration of Phenols and Their Derivatives

Highly regiospecific mononitration of phenols and substituted phenols is accomplished by employing copper(II) nitrate supported on a catalytic amount of zeolite H‐Y in a solid state.     

Preparation,Morphology, and Structure of Thermotropic Liquid Crystalline Polyester-imide/Phenol-formaldehyde Resin Blends

As a novel toughening agent, thermotropic liquid crystalline polymers (TLCPs) possess excellent properties of high strength, high modulus, low expanding coefficient, and high thermal stability. In this study, a thermotropic liquid crystalline poly(ester-imide) derived from N,N’-hexane-1,6-diylbis(tri-millitimide) (IA6), p-hydroxylbenzoic acid (PHB), and 4,4’-dihydroxybenzophenone (DHBP) was synthesized by the Higashi's direct polycondensation method. The structure and properties of the TLCP were studied using Fourier transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetic analyses (TGA), polarized light microscopy (POM), and wide angle X-ray diffraction (WAXD). The results revealed that the synthesized polyester-imide is a nematic TLCP with good thermal stability and its starting decomposition temperature is up to 439°C. Additionally, polymer blends of phenol-formaldehyde (PF) resin with different contents of polyester-imide were prepared and characterized by POM and WAXD. POM results demonstrated that two-step blending is an ideal method for blending TLCP and PF resin. By this method, continuous filamentous stripes can be clearly observed at 230°C for TLCP/PF blend of 10 wt% poly(ester-imide).     

Comparative study to predict toxic modes of action of phenols from molecular structures

Quantitative structure–activity relationship models for the prediction of mode of toxic action (MOA) of 221 phenols to the ciliated protozoan Tetrahymena pyriformis using atom-based quadratic indices are reported. The phenols represent a variety of MOAs including polar narcotics, weak acid respiratory uncouplers, pro-electrophiles and soft electrophiles. Linear discriminant analysis (LDA), and four machine learning techniques (ML), namely k-nearest neighbours (k-NN), support vector machine (SVM), classification trees (CTs) and artificial neural networks (ANNs), have been used to develop several models with higher accuracies and predictive capabilities for distinguishing between four MOAs. Most of them showed global accuracy of over 90%, and false alarm rate values were below 2.9% for the training set. Cross-validation, complementary subsets and external test set were performed, with good behaviour in all cases. Our models compare favourably with other previously published models, and in general the models obtained with ML techniques show better results than those developed with linear techniques. We developed unsupervised and supervised consensus, and these results were better than our ML models, the results of rule-based approach and other ensemble models previously published. This investigation highlights the merits of ML-based techniques as an alternative to other more traditional methods for modelling MOA.     

Rate constants for hydrogen abstraction reactions by the hydroperoxyl radical from methanol, ethenol, acetaldehyde, toluene, and phenol

An important step in the initial oxidation of hydrocarbons at low to intermediate temperatures is the abstraction of H by hydroperoxyl radical (HO(2)). In this study, we calculate energy profiles for the sequence: reactant + HO(2) → [complex of reactants] → transition state → [complex of products] → product + H(2)O(2) for methanol, ethenol (i.e., C(2)H(3)OH), acetaldehyde, toluene, and phenol. Rate constants are provided in the simple Arrhenius form. Reasonable agreement was obtained with the limited literature data available for acetaldehyde and toluene. Addition of HO(2) to the various distinct sites in phenol is investigated. Direct abstraction of the hydroxyl H was found to dominate over HO(2) addition to the ring. The results presented herein should be useful in modeling the lower temperature oxidation of the five compounds considered, especially at low temperature where the HO(2) is expected to exist at reactive levels.     

Nanofluorides

The present review article covers major aspects of inorganic chemistry of nanofluorides, including methods of their synthesis (thermolysis of the precursors, co-precipitation from solutions, reversed micelle technique, hydro- and solvo-thermal techniques, sol–gel method, etc.), nanochemical effects (enhanced chemical activity, self-organization and self-assembly, non-classical mechanism of the single crystal growth, synthesis of non-equilibrium phases), targeted preparation of 1D, 2D, and 3D nanostructures, surface modification of the nanoparticles, fluoride nanocomposites (glass- and nano-ceramics) as well as applications of nanofluorides.