Thermal behavior of some new triazole derivative complexes

A series of new complexes with mixed ligands of the type [ML(C₃H₃O₂)₂]·nH₂O (((1) M=Mn, n=1; (2) M=Co(II), n=2; (3) M=Ni(II), n=4; (4) M=Cu(II), n=1.5; (5) M=Zn(II), n=0; L=3-amino-1,2,4-triazole and (C₃H₃O₂)=acrylate anion) were synthesized and characterised by chemical analysis and IR data. In all complexes the 3-amino-1,2,4-triazole acts as bridge while the acrylate acts as bidentate ligand except for complex (5) where it is found as unidentate. The thermal behaviour steps were investigated in nitrogen flow. The thermal transformations are complex processes according to TG and DTG curves including dehydration, acrylate ion and 3-amino-1,2,4-triazole degradation respectively. The final products of decomposition are the most stable metal oxides, except for complex (4) that leads to metallic copper.     

Permethylated dinuclear Mn(III) coordination nanostructure with stripe-ordered magnetic domains

A di-manganese(III) complex structure was built by an original approach consisting of a two-step procedure. First, the mononuclear complex of the manganese(III) with the Schiff base of the salen-type ligand (H₂L) derived from 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 3,5-di-tert-butyl-2-hydroxybenzaldehyde was prepared. The main feature of note is the 12-membered chelate ring formed upon coordination of the Schiff base to central atom, which adopts a distorted N₂O₄ octahedron environment. In the second step, the acetato co-ligand in this complex is replaced by the carboxylate anion of a dicarboxilic acid, namely adipic acid. This metathesis reaction leads to the formation of dinuclear structure by connecting two manganese centers. The structure, as was determined by X-ray single crystal diffractometry, elemental and spectral analysis, is permethylated dinuclear complex with long aliphatic bridge. Thermal and magnetic properties were studied. In addition, the formation of magnetically induced stripe-ordered domains was highlighted by the magnetic force microscopy (MFM) on films born from diluted solution.     

Enhancing Electrocatalytic Activity through Liquid-Phase Exfoliation of NiFe Layered Double Hydroxide Intercalated with Metal Phthalocyanines in the Presence of Graphene

Earth-abundant transition-metal-based catalysts are attractive for alkaline water electrolysis. However, their catalytic properties are often limited by their poor electrical conductivity. Here, we present a strategy for enhancing the electrical conductivity of NiFe layered double hydroxide (LDH) in order to further improve its properties as an electrocatalyst for the oxygen evolution reaction (OER) in alkaline media. We show that NiFe LDH containing metal tetrasulfonate phthalocyanine in the interlayers between the NiFe oxide galleries can be coupled with graphene during liquid-phase exfoliation by taking advantage of their π-π stacking capabilities. A substantial enhancement in the electrocatalytic activity of NiFe LDH with respect to the OER was observed. Moreover, the activity and selectivity of the catalyst materials towards the oxygen reduction reaction were investigated, demonstrating that both the metal hydroxide layer and the interlayer species contribute to the electrocatalytic performance of the composite material.     

On optimality and duality for multiobjective programming problems involving generalized d-type-I and related n-set functions

In this paper we establish some optimality and duality results under generalized convexity assumptions for a multiobjective programming problem involving generalized d-type-I and related n-set functions.     

局部凸空间中最佳逼近研究纵览

通过对大量文献研究，回顾了最佳逼近论的研究进展．重点讨论了最有意义的可分离局部凸空间最佳逼近问题、以及最佳逼近问题与向量优化、Pareto有效性、多值函数等之间的直接联系．     

On the compatibility of the IPP/PA6/EPDM blends with and without functionalized IPP I. Thermo-oxidative behaviour

Binary isotactic polypropylene (IPP)/polyamide 6 (PA6) and ternary IPP/PA6/ethylene–propylene diene terpolymer (EPDM) blends in various ratios were obtained in a Haake Rheocord mixer. Processing behaviour was changed in the presence of IPP functionalized with bismaleimide (BMI), maleic anhydride (MA) and acrylic acid (AA) as reactive compatibilizing agents. The thermal and thermo-oxidative behaviour of blends was studied by differential scanning calorimetry and thermogravimetry. The functionalized IPPs modify the crystallinity degree and the decomposition behaviour of both IPP and PA6 as a result of chemical reactions of functional groups with those of the PA6. The changes depend on the IPP/PA6 or IPP/PA6/EPDM ratio, the chemical nature and amount of the functionalized IPP. On the basis of the processing and thermal data one can conclude that the compatibilizing agent effect increases in the following order: IPP-AA 相似文献   

Tailored doxycycline delivery from MCM-41-type silica carriers

Doxycycline, an antibiotic from the tetracycline class with a broad spectrum of activity, was used to prepare drug delivery systems based on pristine and functionalized mesostructured silica supports. MCM-41-type materials with different textural, structural, and surface properties were used to assess their influence on the drug release kinetics. Small- and wide-angle XRD, FTIR spectroscopy and N₂ adsorption/desorption isotherms were used to characterize the carriers before and after doxycycline loading. The drug release experiments were performed in vitro in 0.2 M phosphate buffer solution at 37 °C, and the slowest drug release kinetics was obtained for magnesium-modified MCM-41 carrier. All drug-loaded materials exhibited good antibacterial activity against Klebsiella pneumoniae ATCC 10031 strain, similar to the drug alone.     

Thermoxidative Decomposition of Some Polysulfones under Dynamic Conditions of Heating

Kinetic aspects of the first step of thermoxidative decomposition, under dynamic conditions of heating, of some polysulfones have been studied. The dependence of the kinetic parameters on the heating rate and conversion degree has been established. The compensation effect and conversion function have also been discussed. Polysulfone decomposes by the breaking of the main chain, a process involving very high activation energy. Chemically modified polysulfones show the first step of thermoxidative decomposition at relatively low temperatures. This step corresponds to the elimination of functional side - groups for the bromomethylated polysulfone while in the case of the carboxylated polysolfone, the loss of the carboxyl group is probably accompanied by a crosslinking reaction. This revised version was published online in July 2006 with corrections to the Cover Date.     

On the compatibility of binary and ternary random copolymers of acrylonitrile with vinyl acetate and/or α-methylstyrene—II: The influence of the time factor

The time dependence of the microscopical aspect, crystallinity, viscosity of the spinning solutions and the thermal and tinctorial properties of films formed from binary, ternary copolymers and binary copolymer mixtures of acrylonitrile with vinyl acetate and χ-methylstyrene have been compared. The characteristics of binary copolymers and incompatible mixtures are stable with time, while those of ternary copolymers and pseudocompatible mixtures evolve towards a limiting state. with phase separation.     

Side chain thermotropic liquid crystalline polysulfone obtained from polysulfone udel by chemical modification

Polysulfone udel was chemically functionalized with chloromethylene functional groups via the chloromethylation reaction. A new azomethine dimesogen containing one phenolic hydroxyl functional group was recently synthesized and proved to exhibit a large nematic mesophase range in the liquid state. Further reaction of the dimesogen with the functionalized polysulfone using a transquaternization reaction led to new polysulfones bearing pendant rigid dimesogenic units--no spacer being involved in the chemical design of the polymer. The polymers were characterized by IR, ¹H NMR spectroscopy techniques, and their thermotropic liquid crystallinity behaviour was studied by optical polarizing microscopy (PLM) and DSC measurements. Enantiotropic nematic mesophases were observed under the PLM. A dependence of the melting temperature on the degree of substitution was noticed.