s-Triazole systems. Part IV: Novel substituted thio-s-triazole derivatives

Interaction of (3-aryloxymethyl-4-phenyl-striazol-5-yl)thioacethydraz-ide ( la -c) with phenyl isocyanate and/or with methyl/phenyl isothiocyanate gave semicarbazides ( 2a -c) and thiosemicarbazides ( 3a-f ) respectively. Cyclization of ( 3a-f ) yielded s-triazoles ( 4a-f ). Compounds 4b,d,f were easily alkylated giving S-substituted thio-s-triazoles ( 5a-e ). Furthermore, compounds 4b,d,f underwent a Mannich reaction to give the expected Mannich bases ( 6a-f ). All compounds were fully confirmed by elemental and spectral analyses and have been screened in vitro, for antimicrobial activity.     

The reversible oxidation of aromatic cation radicals to dications. Solvents of low nucleophilicity

Reversible behavior for both electron transfers for oxidation of aromatic compounds to cation radicals and dications was observed in several common electrolytic solvents. Nitriles, nitro compounds and dichloromethane can all be rendered essentially nucleophile free for voltammetric purposes simply by conducting the voltammetric measurements over neutral alumina shortly after the mixture has been stirred. Solvents containing trifluoroacetic acid and the corresponding acid anhydride are not only useful for voltammetry but can also be used to prepare stable solutions of cation radicals and dications. Equilibrium constants for the disproportionation of cation radicals to dications were calculated from the reversible electrode potentials and the effect of changes in the solvent system on the equilibrium constants is discussed.     

Thermally stable polyimide binders from aromatic dianhydrides and acetyl derivatives of aromatic diamines: Formation mechanism

Polyimide resins based on dianhydrides of aromatic tetracarboxylic acids and acetyl derivatives of aromatic diamines have been developed for impregnating carbon fibers and glass cloth. Binder prepolymers are soluble in amide solvents and acetone and also form melts with a viscosity of 0.1–0.3 Pa · s at 250–300°C. The melt lifetime is 20–30 min. An increase in temperature leads to the formation of a crosslinked insoluble system of high thermal stability. The formation of polyimide binders was studied with the aid of IR and NMR spectroscopy. A mechanism of the reaction of aromatic dianhydrides with acylated amines is proposed. On the basis of polyimide binders from dianhydride of 3,3′,4,4′-benzophenonetetracarboxylic acid and bis-[4-acetaminophenyl]-sulfone, bis-[4-acetaminophenyl]-ether, and N,N-diacetyl-p-phenylene diamine, carbon fiber composites with good physico-mechanical properties were obtained.     

Some aromatic derivatives of 1,4,7,10,13,16-hexaoxacyclooctadecane

Summary Some of the derivatives of polyglycoles were obtained just by reacting the -chlorhydrines with phenols, -naphtol and -naphtols in the presence of NaOH. Derivatives obtained were condensed with the ditosylates of polyethyleneglycoles in the presence of potassium tert-butoxide in THF and some asymmetrical mono and disubstituted hexaoxacyclooctadecanes were formed.Submitted for the fullfilment of Ph.D.degree in Organic Chemistry. Diyarbakir University, 1981     

Curing of new trimellitimide glycidyl ester derivatives with aromatic diamines

The cure behaviour of new epoxy resins containing a preformed imide ring with m-phenylenediamine (mPDA) and diaminodiphenylmethane (DDM) was investigated. The progress of polymerization was followed by recording IR and ¹³C-NMR spectra at time intervals. The curing proceeded mainly by chain extension at low temperatures, the reaction being not very fast, whereas crosslinking occurred as the gel point was reached (about 15 h at 60°C) by reaction of secondary amino groups with epoxides. Impurities influence, playing the part of catalysts, could be determined from the reaction rate of glycidyl and amino groups. So a kinetic study was made. The thermal behaviour of these cured epoxy resins was also studied.     

Indirect electrolytic oxidation of some aromatic derivatives

High current efficiencies and material yields were attained in the indirect electrochemical oxidation of toluene and chlorotoluene to the corresponding aldehyde. The oxidant used was Ce⁴⁺ in HClO₄, which was regenerated at platinized titanium anodes. A cost estimate showed that the electrochemical route could be economically attractive.     

Novel chalcone-based aromatic polyamides: synthesis,characterization, and properties

Two novel diacid-based monomers have been synthesized by anchoring a benzylideneacetophenone (chalcone) moiety through an amide or ester bridge at the fifth position of the isophthalic acid ring. Two series of new polyamides bearing chalcone side chains were prepared by direct polycondensation reaction of the aforementioned dicarboxylic acids and various aromatic diamines in N-methyl-2-pyrrolidinone, using triphenyl phosphite and pyridine as condensing agents. Their molecular structure and the basic properties were investigated by nuclear magnetic resonance, Fourier-transform IR and UV–vis spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and wide-angle X-ray diffraction. The inherent viscosity, molecular weights measurements (by gel permeation chromatography), water uptake, and solubility tests completed the research study. Introduction of the rigid and bulky chalcone units into the polymer side chains improved remarkably the solubility of the aromatic polyamides, endowed them with an amorphous nature, good thermal stability, and photosensitivity. The resulting polymers were obtained in good yields, inherent viscosities varied between 0.49 and 0.86 dL/g, and their relative high molecular weights conferred them film-forming properties. They were soluble in amide-type polar solvents, such as N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. These polyamides had glass transition temperatures between 219 and 264 °C, and 10% weight loss temperatures in the range of 394–436 °C and around 50% residue at 700 °C in nitrogen atmosphere. The polyamides underwent a [2 + 2] photocycloaddition reaction upon UV light irradiation both in solution and film state in the absence of a photoinitiator or photosensitizer. The polymer films became insoluble in solvents as a result of the crosslinking .     

Unsaturated para-linked aromatic LC polyesters: Thermotropic and lyotropic systems

Liquid-crystalline thermosets (LCT) are a new class of materials which combine typical properties of LC polymers with those of conventional thermosets. This article reports on the development of a lyotropic LC thermoset (LLCT) in which the solvent is a vinyl monomer. Such an LLCT is expected to have several advantages compared to conventional unsaturated polyester resins. The synthesis and characterization of a variety of novel substituted para-linked aromatic polyesters and copolyesters containing unsaturated fumaroyl units is presented. The thermal and liquid crystal properties were investigated. It is demonstrated that it is possible to prepare a lyotropic LC solution in styrene. These lyotropic solutions are capable of thermal crosslinking by the addition of a free-radical initiator. © 1995 John Wiley & Sons, Inc.     

Synthesis and characterization of luminescent copolyethers with alternate stilbene derivatives and aromatic 1,3,4-oxadiazoles

New copoly(aryl ether)s containing alternate stilbene (P1), distyrylbenzene (P2), or distyrylstilbene (P3) chromophores and aromatic 1,3,4-oxadiazole were prepared by nucleophilic polycondensation. The copolyethers are basically amorphous materials with decomposition temperature greater than 250 °C. Introduction of side hexyloxy groups to distyrylbenzene chromophores in P2 significantly enhanced its solubility in common organic solvents such as toluene, THF, and chloroform. UV/visible and fluorescence spectrometers were employed to investigate their optical properties both in solution and in film state, whereas cyclic voltammograms were used to estimate their band diagrams. Photoluminescence maxima of P1, P2 and P3 are 442, 540 and 528 nm, respectively. Oxadiazole chromophores in backbone enhance electron affinity, whereas pendant hexyloxy groups decrease ionization potential. The threshold voltage and luminance of ITO/P2 (100 nm)/Al single layer device are 17 V and 950 cd/m², respectively.     

Novel perfluoroalkyl phthalocyanine metal derivatives: Synthesis and photodynamic activities

Novel perfluoroalkyl phthalocyanine metal derivatives with four perfluorobutyl or four perfluorohexyl groups were synthesized by a two-step procedure starting from 4-iodophthalonitrile; the preparation of the key intermediate 4-(perfluorohexyl)phthalonitrile was optimized. Values of fluorescence quantum yield in ethanol of 0.11 and 0.38 were obtained for zinc(II) tetra (perfluorobutyl)phthalocyanine and zinc(II) tetra (perfluorohexyl) phthalocyanine, respectively. The photodynamic activities of two, zinc (II) phthalocyanine derivatives upon both HL-60 leukemic cells and A375 melanotic cancer cells in vitro were investigated revealed that the cell viability was slightly better in the case of HL-60 than A375.     

Novel aromatic macrocyclic oligomers: intermediates for the preparation of high-performance polymers

Recent studies aimed at the development of macrocyclic oligomers as the intermediates for the preparation of high-performance polymers are reviewed. Efficient methods for the preparation of a range of cyclic oligomers, such as aryl ether ketones, aryl ether phthalazines, aryl ether isoquinolines, aryl ether phthalazinones, and arylene sulfides, have been developed. Cyclization was achieved via a nucleophilic aromatic substitution reaction under high-dilution conditions. The cyclic aryl ether oligomers undergo a facile ring-opening polymerization to form high molecular weight polymer. Cyclic oligomers containing an aromatic sulfide linkage also undergo a facile free-radical ring-opening polymerization to form high molecular weight polymers which can be amorphous or crystalline. Due to their low molecular weights, these cyclic oligomers have very low melt viscosities which makes them attractive intermediates for a variety of applications for which the conventionally prepared high molecular weight polymers would not be suitable.     

Novel aromatic polyimide fiber with biphenyl side‐groups: Dope synthesis and filament internal morphology control

A new organic‐soluble aromatic polyimide with biphenyl side‐groups has been synthesized from 4,4′‐oxydiphthalic anhydride and 3,5‐diamino‐benzonic‐4′‐biphenyl ester (DABBE) via a one‐step polymerization in m‐cresol. A higher molecular weight polyimide has been obtained by the addition of chlorotrimethylsilane (TMSCl) in the solution of DABBE to form, in situ, silylated diamine. The optimum mole amount of TMSCl relative to the number of amino groups is 100%. This polyimide is soluble in m‐cresol, allowing fibers to be spun from isotropic solution using a dry‐jet wet spinning method. Based on a ternary phase diagram of m‐cresol, ethanol, and water, controlling of the internal morphology of as‐spun fibers has been achieved by varying the rate of polyimide coagulation through adjustment of nonsolvent/solvent miscibility in the coagulation bath. Scanning electron microscopic pictures show that filament internal morphologies ranged from porous‐like to fully solid. The solid as‐spun fibers can be drawn at high temperatures (>330°C) under tension to high drawn ratios (up to 6×), which produces a remarkable increase in tensile strength to about 1.0 GPa and an initial modulus higher than 60 GPa. POLYM. ENG. SCI. 46:123–128, 2006. © 2005 Society of Plastics Engineers     

Novel electrochromic aromatic poly(amine-amide-imide)s with pendent triphenylamine structures

Three new aromatic poly(amine-amide-imide)s (PAAIs) having pendent triphenylamine units were prepared from the phosphorylation polyamidation reactions of a newly synthesized diamine, N,N-bis(4-aminophenyl)-N′,N′-diphenyl-1,4-phenylenediamine, with three imide ring-preformed dicarboxylic acids. These PAAIs had inherent viscosities of 0.54-0.86 dL/g, and they were amorphous and readily soluble in many organic solvents and could be solution cast into transparent, tough, and flexible films with good mechanical properties. They displayed relatively high glass-transition temperatures (279-287 °C) and good thermal stability, with 10% weight-loss temperatures in excess of 522 °C in nitrogen and char yields at 800 °C in nitrogen higher than 67%. The solutions of polymers in NMP exhibited strong UV-vis absorption bands with a maximum around 315 nm. The hole-transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the PAAIs prepared by casting polymer solution onto an indium-tin oxide (ITO)-coated glass substrate exhibited two reversible oxidation redox couples at 0.67 and 1.08 V vs. Ag/AgCl in acetonitrile solution. All the PAAIs revealed very stable electrochromic characteristics, changing color from original pale brownish to green, and then to blue at 0.67 and 1.08 V, respectively.     

Novel electroactive aromatic polyamide with oligoanilines and azo groups in the backbone: synthesis, characterization and dielectric properties

A novel electroactive polyamide with alternating amino-capped aniline pentamer and azo groups in the main chain was synthesized via a four-step synthetic procedure. The characteristics of the obtained polyamide were studied in detail by Fourier-transform infrared (FTIR) spectra, nuclear magnetic resonance (¹H NMR) and gel permeation chromatography (GPC). The thermogravimetric analysis (TGA) was used to evaluate its thermal characteristics, and the result showed the as-synthesized polymer had a good thermal stability. Besides, the electrochemical behavior of the polyamide was checked by cyclic voltammetry (CV) and the mechanism of electrochemical oxidation process was well studied. Furthermore, UV–vis spectra were used to monitor the doping process and photoisomerization process of the polyamide. Ratifying results were obtained in the investigation on dielectric properties of the as-synthesized polymer. The dielectric constant was greatly increased by treating the conjugated oligoaniline segments with hydrochloric acid.     

Novel phosphorilated flame retardant thermosets: epoxy-benzoxazine-novolac systems

Modified novolac resins with benzoxazine rings were prepared and cured with isobutyl bis(glycidylpropylether) phosphine oxide (IHPOGly) as crosslinking agent. Their curing behaviour using different epoxy/phenol molar ratios and with or without triphenylphosphine as catalyst was studied. Two different phenolic groups react with oxirane ring, those initially free and those generated after benzoxazine ring opening. In absence of catalyst, it is not possible to distinguish between them. However, for the catalyzed curing of the highest modification degree benzoxazine based novolac resin is possible to distinguish both reactions. The thermal, thermomechanical and flame retardant properties of the cured materials were measured. V-O materials were obtained when the resins were tested for ignition resistance with the UL-94 test.     

二安替比林甲烷芳环衍生物的合成及其光度性质的研究

合成了DAPVM,DA-o-CM,DA-m-CM,DASM,DADMM,DAPM,DAMAM,DANM,DAHMM等9个二安替比林甲烷芳香族衍生物,其中DA-o-CM和DA-m-CM为首次合成。研究了在 H_3PO_4介质中和Mn(Ⅱ)存在下其与Cr(Ⅵ)、V(V)、Ce(Ⅳ)的显色反应。开发了几个试剂的应用体系,显示了良好的应用前景。     

Novel aromatic polyimide ionomers for proton exchange membranes: Enhancing the hydrolytic stability

In the pursuit of the hydrolytically stable sulfonated polyimide (SPI) membranes with high proton conductivity for fuel cell applications, a series of novel SPI ionomers derived from benzophenone-4,4′-bis(4-thio-1,8-naphthalic anhydride) (BPBTNA) were conveniently synthesized. The accelerated water stability tests demonstrated that the resultant SPI membranes kept highly the original mechanical properties even after 24 h in water at 140 °C. The membranes exhibited a microphase-separated structure with high morphological stability, and well-collected hydrophilic domains that could work as proton transport channels. The proton conductivity of 1c with an IEC of 1.90 meq g⁻¹ was higher than that of Nafion at 100% relative humidity (RH).     

Synthesis and fluorescent property of some novel benzothiazoyl pyrazoline derivatives containing aromatic heterocycle

A series of novel benzothiazoyl pyrazoline compounds containing aromatic heterocycle were synthesized, whose structure were confirmed by means of IR, ¹H NMR, UV and elementary analysis. The fluorescent spectra showed that these compounds have good blue fluorescence. The fluorescence emission wavelengths are about 450 nm.     

Novel olygomeric C-3 esters of betulin derivatives

Novel copolymers of C-3 esters of betulin derivatives (3-hydroxy-1-cyano-2,3-seco-2-nor-19β,28-epoxyoleane 3-O-vinylbenzoate (I), 3-hydroxy-1-cyano-2,3-seco-2-nor-19β,28-epoxyoleane 3-O-vinylacetate (II), methyl 3-hydroxy-1-cyano-2,3-seco-2-norlup-20(29)-en-28-oate 3-O-vinylbenzoate (III)) with N-vinylpyrrolidone and acrylonitrile have been prepared by free radical copolymerization. Kinetic regularities of the process were investigated. New water-soluble silver nanocomposites based on (III) copolymer with N-vinylpyrrolidone [poly((III)-VP)] have been developed. The average silver particle size ranged from 40 to 52?nm, with the corresponding UV–vis absorption peak position at 400?nm. The nanocomposite obtained has a significant cytotoxic activity toward melanoma cell line and may be considered for the development of new materials for medical applications.