Synthesis, structural characterization and electrochemical studies of new macrocyclic Schiff base containing pyridine head and its metal complexes

A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:13,14-tribenzo-9,12-dioksa-cyclopentadeca-1,5-diene was synthesized by reaction of 2,6-diaminopyridine and 1,2-bis(2-carboxyaldehyde phenoxy)ethane. Then, its Cu(II), Ni(II), Pb(II), Co(III) and La(III) complexes were synthesized by the template effect by the reaction of 2,6-diaminopyridine and 1,2-bis(2-carboxyaldehyde phenoxy)ethane and Cu(NO₃)₂ · 3H₂O, Ni(NO₃)₂ · 6H₂O, Pb(NO₃)₂, Co(NO₃)₂ · 6H₂O, La(NO₃)₃ · 6H₂O, respectively. The ligand and its metal complexes have been characterized by elemental analysis, IR, ¹H and ¹³C NMR, UV-Vis spectra, magnetic susceptibility, thermal gravimetric analysis, conductivity measurements, mass spectra, and cyclic voltammetry. All complexes are diamagnetic and Cu(II) complex is binuclear. The Co(II) was oxidized to Co(III). The comparative electrochemical studies show that the nickel complex exhibited a quasi-reversible one-electron reduction process, while copper and cobalt complexes gave irreversible reduction processes in DMSO solution.     

A mass conservative well‐balanced reconstruction at wet/dry interfaces for the Godunov‐type shallow water model

This paper presents a novel mass conservative, positivity preserving wetting and drying treatment for Godunov‐type shallow water models with second‐order bed elevation discretization. The novel method allows to compute water depths equal to machine accuracy without any restrictions on the time step or any threshold that defines whether the finite volume cell is considered to be wet or dry. The resulting scheme is second‐order accurate in space and keeps the C‐property condition at fully flooded area and also at the wet/dry interface. For the time integration, a second‐order accurate Runge–Kutta method is used. The method is tested in two well‐known computational benchmarks for which an analytical solution can be derived, a C‐property benchmark and in an additional example where the experimental results are reproduced. Overall, the presented scheme shows very good agreement with the reference solutions. The method can also be used in the discontinuous Galerkin method. Copyright © 2016 John Wiley & Sons, Ltd.     

Cyclohexenones Through Regioselective Addition of 1,3-Dicarbonyl Compounds to Terpenoid-Like Bischalcones

Terpenoid-like bischalcones (3 and 4) were synthesized from the reaction of α- and β-ionones and benzaldehydes in excellent yields. The Michael addition of 1,3-dicarbonyl compounds to bischalcones (3 and 4) resulted in the formation of cyclohexenones derivatives (10a–d and 14a, b) via regioselective addition of 1,3-dicarbonyls and then cyclization.     

Nanocomposite Mullite/Mullite Powders by Spray Pyrolysis

A mullite/mullite nanocomposite powder has been synthesized, composed of nanometer-size 3Al₂O₃·2SiO₂ (3/2) mullite precipitates within a matrix of the high alumina 2Al₂O₃·SiO₂ (2:1) mullite. Historically, the transition from the metastable high-alumina phase to the thermodynamically stable 3:2 phase of mullite has been thought to be a continuous process, involving a continuous solid solution between the two forms of mullite. In contradiction to this widely held view, our high resolution transmission electron microscopic characterization confirms that a first order phase transition between two distinct mullites occurs. The high degree of interface coherence between the precipitates and the matrix allows us to speculate that the mechanical properties of the matrix could be enhanced by a process similar to the precipitation hardening of metals.     

Manganese(III) Acetate Catalyzed Oxidative Radical Additions of α‐Dicarbonyl Compounds to 1‐ and 2‐Phenylcyclohepta‐1,3,5‐triene

Manganese(III) acetate catalyzed oxidative radical‐addition reactions of α‐dicarbonyl compounds such as methyl acetoacetate ( 6 ), acetylacetone ( 7 ), and dimedone ( 8 ) to the mixture of 1‐ and 2‐phenylcyclohepta‐1,3,5‐triene ( 4 and 5 ) were investigated (Scheme 1). The 1‐phenylcyclohepta‐1,3,5‐triene ( 4 ) formed mainly [2+3] and [4+3] dihydrofuran addition products derived from cycloheptatriene and [2+3] dihydrofuran addition products derived from the norcaradiene structure. The 2‐phenylcyclohepta‐1,3,5‐triene ( 5 ) formed mainly [6+3] dihydrofuran addition products derived from cycloheptatriene and [4+3] dihydrofuran addition products derived from the norcaradiene structure. The structures of isolated products were established by their spectroscopic data (IR, ¹H‐ and ¹³C‐NMR, MS, and elemental analysis) and comparison with literature data. The formation mechanism of the products is discussed.     

Phenacenes from Diels-Alder trapping of photogenerated o-xylylenols: phenanthrenes and benzo[e]pyrene bisimide

[structure: see text] The synthesis of phenanthrene and benzo[e]pyrene bisimides, 1 and 2, was accomplished via the Diels-Alder trapping of sterically congested o-xylylenols photochemically generated from 3,6-dibenzoyl-o-xylene and 1,4-dibenzoyl-9,10-dihydroanthracene, respectively. Absorption and emission from 2 are red-shifted from 1 and unsubstituted benzo[e]pyrene. The fluorescence quantum yield for 2 is an order of magnitude lower than that of 1 and comparable to that of the parent benzo[e]pyrene.     

The effects of low dose leukotriene receptor antagonist therapy on airway remodeling and cysteinyl leukotriene expression in a mouse asthma model

Airway structural changes that occur in patients with asthma in response to persistent inflammation are termed airway remodeling. The cysteinyl leukotrienes (LTC(4), D(4) and E(4)) are known to play important roles in the pathobiology of asthma. To evaluate the effect of low dose montelukast (MK) on the development of airway remodeling using a chronic murine model of allergic airway inflammation with subepithelial fibrosis, BALB/c mice, after intraperitoneal ovalbumin (OVA) sensitization on days 0 and 14, received intranasal OVA periodically on days 14-75. MK treated mice received montelukast sodium intraperitoneally on days 26-75. The OVA sensitized/challenged mice developed an extensive eosinophil cell inflammatory response, goblet cell hyperplasia, mucus occlusion, and smooth muscle hypertrophy of the airways. In addition, in OVA sensitized/challenged mice, dense collagen deposition/fibrosis was seen throughout the lung interstitium surrounding the airways, blood vessels, and alveolar septae. The cysteinyl leukotriene 1 (CysLT1) receptor antagonist, MK significantly reduced the airway eosinophil infiltration, goblet cell hyperplasia, mucus occlusion, and lung fibrosis except airway smooth muscle hypertrophy in the OVA sensitized/challenged mice. The OVA sensitized/challenged mice had significantly increased epithelial desquamation compared with control mice. MK markedly reduced epithelial desquamation of airways in OVA/MK treated animals compared with OVA sensitized/challenged mice. MK treatment did not affect the levels of CysLT in lung tissue. Our results show that the important role of cysteinyl leukotrienes in the pathogenesis of asthma. Lower dose of CysLT1 receptor antagonism has a significant anti-inflammatory effect on allergen-induced lung inflammation and fibrosis but not airway smooth muscle hypertrophy in an animal model of asthma.     

Reactions of 1‐amino‐5‐benzoyl‐4‐phenyl‐1H‐pyrimidine‐2‐one with carboxylic anhydrides: Experimental data and AM1 calculations

1‐Amino‐5‐benzoyl‐4‐phenyl‐1H‐pyrimidine‐2‐one 1 reacts with several carboxylic anhydrides 2a‐d under different conditions and gives new amide and imide derivatives. The structure of these compounds, 3a‐d , are determined by spectroscopic methods. Electronic and geometric structures of reactants, transition states, intermediates and final products of the reaction are calculated by the AM1 method. Transition states are further confirmed by vibrational analysis (computation of force constants analytically) and characterized by the corresponding imaginary vibration modes and frequencies.     

Multiple rogue wave and solitary solutions for the generalized BK equation via Hirota bilinear and SIVP schemes arising in fluid mechanics

The multiple lump solutions method is employed for the purpose of obtaining multiple soliton solutions for the generalized Bogoyavlensky-Konopelchenko(BK) equation. The solutions obtained contain first-order, second-order, and third-order wave solutions. At the critical point,the second-order derivative and Hessian matrix for only one point is investigated, and the lump solution has one maximum value. He's semi-inverse variational principle(SIVP) is also used for the generalized BK equation. Three major cases are studied, based on two different ansatzes using the SIVP. The physical phenomena of the multiple soliton solutions thus obtained are then analyzed and demonstrated in the figures below, using a selection of suitable parameter values.This method should prove extremely useful for further studies of attractive physical phenomena in the fields of heat transfer, fluid dynamics, etc.     

Kinetics and thermodynamics of the adsorption of some dyestuffs and p-nitrophenol by chitosan and MCM-chitosan from aqueous solution

The effect of initial concentration, temperature, and shaking rate on the adsorption of three dyestuffs [orange II (O-II), crystal violet (CV), and reactive blue 5 (RB5)] and an ideal adsorbate, p-nitrophenol (PNP), by chitosan (Sigma C-3646) and the effect of temperature on the adsorption of O-II and CV by monocarboxymethylated chitosan (MCM-chitosan) were investigated. Kinetic data obtained for the adsorption of each dyestuff and PNP by chitosan and of O-II and CV by MCM-chitosan at different temperatures were applied to the Lagergren equation, and adsorption rate constants (k(ads)) at these temperatures were determined. These rate constants related to the adsorption of O-II and RB5 by chitosan and of O-II by MCM-chitosan were applied to the Arrhenius equation, and activation energies (E(a)) were determined. In addition, the isotherms for adsorption, at different temperatures, of each dyestuff and PNP by chitosan and of O-II and CV by MCM-chitosan were also determined. These isothermal data were applied to linear forms of isotherm equations that they fit, and isotherm constants were calculated. Because the isotherm curves obtained for the adsorption of O-II and CV by chitosan and of CV by MCM-chitosan fit the Langmuir adsorption isotherm, b constants were applied to thermodynamic equations, and thermodynamic parameters (delta G, delta H, and delta S) were calculated. Lastly, chitosan and MCM-chitosan were compared with respect to the ability to take up the dyestuffs and PNP.