Intercalation of Azo Compounds into Layered Aluminium Dihydrogentriphosphate and a Layered Double Hydroxide

The inner surfaces of inorganic layered compounds such as aluminium dihydrogen-triphosphate (ADHP) and layered double hydroxide (LDH) were modified by azo compounds. Upon intercalation of 4-phenylazoaniline and 4,4-azodianiline into ADHP, the interlayer spacing increased from 6.4 to 21.5 Å and 20.6 Å, respectively. The intensity of IR peaks due to P-–OH of ADHP and amino groups of guests decreased by the thermal treatment of the intercalates. The interlayer spacings also decreased to 16.9 Å and 16.7 Å, respectively, indicating a dehydration reaction between P–-OH and amino groups. The LDH inner surface was modified by the reaction with trans-p-phenylazobenzoylchloride (PAB-Cl). Upon surface modification, the interlayer spacing increased from 7.6 Å to about 27 Å. The absorption of this surface-modified LDH near 410 nm increased upon irradiation with UV light and decreased upon irradation with visible light, indicating the occurrence of trans–cis isomerization of PAB-Cl between the layers.     

Polycondensation of pyridine-2,6-dicarboxylic acid with some di- and tetraamino compounds

Pyridine-2,6-dicarboxylic acid phenyl ester was condensed with 3,3′-diaminobenzidine and 3,3′,4,4′-tetraaminodiphenyl ether. Polyamides were also synthesized by condensation of the above ester with p-phenylenediamine, benzidine, 4,4′-diaminodiphenyl sulfide and 4,4′-diaminodiphenyl sulfone. These amides had higher inherent viscosities and greater thermal stability than was reported before. Model compounds of imidazoles were prepared by condensation of the same ester with o-phenylenediamine and 2,3-diaminopyridine and of polyamides by condensation with aniline and 2-aminopyridine. In the case of the polyimidazole, the completely closed ring of imidazole did not form. The ultraviolet spectra of model compounds were compared with those of the polymers. The thermogravimetric curves show that the polymers are stable up to more than 400°C under argon atmosphere. All polymers were insoluble in most organic and inorganic solvents. They dissolved only partially in DMSO and DMF. Inherent viscosity was measured for the soluble polymer fraction.     

Chemical trapping experiments support a cation-radical mechanism for the oxidative polymerization of aniline

The oxidative polymerization of aniline in aqueous acidic solution was carried out in the presence of a variety of organic compounds as potential traps for postulated intermediates. The polymerization was inhibited by hindered phenols and electron-rich alkenes, traps for cation-radicals. However, polyaniline was still obtained in the presence of electron-rich arenes, such as 1,3-dimethoxybenzene and 1,4-dimethoxybenzene, known as excellent receptors of nitrenium ions. Polymerization of N-phenyl-1,4-phenylenediamine was similarly carried out in the presence of potential traps. Polyaniline containing an N-phenyl group was obtained in the presence of 1,3-dimethoxybenzene and 1,4-dimethoxybenzene. Hindered phenols and 4-methoxystyrene only slightly inhibited polymerization of N-phenyl-1,4-phenylenediamine which most probably proceeded by way of the stable diarylamino radical. Copolymerization of aniline with 10 wt % of N-phenyl-1,4-phenylenediamine in the presence of these traps gave similar results to the polymerization of pure aniline. These results have led to the proposed cation-radical polymerization mechanism of aniline, in which the polymerization is a chain growth reaction through the combination of a polymeric cation-radical and an anilinium cation-radical. Step growth character is also present when a polymeric aminium cation-radical end combines with a diarylaminoended polymer. The copolymerization of N-phenyl-p-phenylenediamine can also occur by reaction of aniline cation-radical with a polyarylamine radical. The nitrenium mechanism was further rejected by the fact that attempted polymerization of N-phenylhydroxylamine, which forms authentic nitrenium ions in acid, failed to give polymer. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2569–2579, 1999     

The preparation of conducting polyaniline–silver and poly(p-phenylenediamine)–silver nanocomposites in liquid and frozen reaction mixtures

The oxidation of aniline with silver nitrate in 1 mol L⁻¹ acetic acid at 20 °C yielded a composite of two conducting components, polyaniline and silver; the acceleration with 1 mol% of p-phenylenediamine is needed for efficient synthesis. The yield and molecular weight increased when aniline was copolymerized with 10 mol% p-phenylenediamine. Such product displayed metallic conductivity below 180 K and semiconductor type above this temperature. As the result, the conductivity was the same at 100 and 300 K. The oxidation of p-phenylenediamine alone with silver nitrate also produced a conducting composite having the conductivity of 1,750 S cm⁻¹ despite the assumed nonconductivity of poly(p-phenylenediamine). The present study demonstrates that all oxidations proceeded also in frozen reaction mixtures at −24 °C, i.e., in the solid state. In most cases, molecular weights of polymer component increased, the conductivity of composites with silver improved, to 2,990 S cm⁻¹ for poly(p-phenylenediamine)–silver, and remained high after deprotonation with 1 mol L⁻¹ ammonium hydroxide.

     

Calculation of henry constants for the adsorption of isomeric phenylenediamines on graphitized thermal carbon black

Henry constants for the adsorption of o- and p-phenylenediamines on the surface of graphitized thermal carbon black within the temperature range 433–479 K were calculated by the molecular statistical method. The parameters of the atom-atom potential function of intermolecular interaction between the nitrogen atom in aniline and isomeric phenylenediamines and the carbon atom of the basal face of graphite were determined. It was shown that an intramolecular H bond influenced the geometry and adsorption properties of o-phenylenediamine.     

Oligomer-immobilizing ability of an electrodeposited aramid resin film in the electrooxidation of aniline derivatives and the functions of the resulting films

An aramid resin, poly(p-phenylene terephthalamide) (PPTA), was electrodeposited on an indium-tin oxide electrode as a mechanically stable film from a dimethyl sulfoxide solution. Two aniline derivatives, o-phenylenediamine and o-aminophenol, were electrooxidized from H₂SO₄ aqueous solutions using the PPTA film-coated electrode. The PPTA film was permeable to the aniline derivatives, and the derivatives were electrooxidized on the electrode surface. When the derivatives were electrooxidized, the film immobilized the corresponding oligomer species as well as the polymers plain (o-phenylenediamine) (PoPD) and poly(o-aminophenol) (PoAP), and the deposited amount of the polymers was increased by the PPTA film. The immobilized amount of PoAP was greater than that of PoPD because of the 1,4-substituted structure of PoAP. In the PPTA film, both PoPD and PoAP were electronically stabilized, and they became durable against oxidative degradation.     

Radical Products in the Chemical Oxidationof Amines. An ESR Study of Secondary CationRadicals from Aniline and Derivatives of 1,2-Phenylenediamine

Summary.  The oxidation of aniline and some derivatives of 1,2-phenylenediamine was performed by the system Pb(CH₃COO)₄—CF₃COOH—CH₂Cl₂. An ESR investigation of the oxidized aniline confirmed the presence of secondary cation radical. Its structure was determined by comparison of its ESR spectrum with those of cation radicals prepared from derivatives of 1,4-phenylenediamine. The oxidation of 1,2-phenylenediamine and its derivatives leads to the formation of either primary or secondary cation radicals, the latter having the character of substituted dihydrophenazinium cation radicals. Received August 17, 2000. Accepted (revised) October 16, 2000     

Electrochemical behavior of a new electroactive polyimide derived from aniline trimer

The electrochemical behavior of a soluble polyimide (Tani-polyimide) derived from an aniline trimer was investigated. Similar to processes observed in polyaniline, two typical redox processes involving protonation and ion insertion were observed. Due to the presence of an isolated, short quinonediimine or N,N′-diphenyl-p-phenylenediamine segment, Tani-polyimide displayed an electroactivity at higher potentials and did not undergo an electrochemical degradation reaction. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4295–4301, 1999     

A novel synthetic method to phenyl-capped penta- and hexaaniline

A new convenient method is reported for the synthesis of the phenyl-capped pentamer and hexamer of aniline. The method was accomplished by the reaction of the parent aniline tetramer in the pernigraniline oxidation state with diphenylamine and N-phenyl-1,4-phenylenediamine in the leucoemeraldine oxidation state, respectively. The mechanism probably involves the formation of cation radicals and their coupling.     

Study of capacitive properties in supercapacitor for copolymer of aniline with m-phenylenediamine

The copolymers were synthesized with different molar ratios of m-phenylenediamine to aniline (R for short) by a chemical oxidation method. The products were first used as electrochemical activity materials of the supercapacitor. Capacitive behaviors of the prepared copolymers in 1 mol·L⁻¹ H₂SO₄ electrolyte were examined by electrochemical impedance spectroscopy, cyclic voltammeter, and galvanostatic charge/discharge. The relationship of molar ratios with capacitive property of the prepared products was investigated too. The results showed that the product with R of 2:98 displayed better electrochemical properties than that of the other products. Compared with the synthesized polymer in the absence of m-phenylenediamine, the polymerized copolymer with R of 2:98 exhibited the initial specific capacitance value of 475 F·g⁻¹, which increased by nearly 10.1% than that of the former at a current density of 200 mA·g⁻¹ in 1 mol·L⁻¹ H₂SO₄ electrolyte in the potential range of −0.3 to 0.7 V. The discharge specific capacitance value of the copolymer remained 300 F·g⁻¹ after 1,000 cycles, exhibiting a good cycling performance and the structure stability.     

六、七元瓜环与苯二胺及硝基苯胺异构体相互作用的HPLC研究

利用HPLC法考察了六、七元瓜环(Q[6], Q[7])与邻苯二胺(g1)、间苯二胺(g2)、对苯二胺(g3)、邻硝基苯胺(g4)、间硝基苯胺(g5)、对硝基苯胺(g6)的相互作用. 实验结果表明: Q[6]可与客体g1～g3, g5形成1∶1的包结配合物; Q[7]与客体g1～g6形成1∶1包结配合物, 同时计算了包结配合物的包结稳定常数, 探讨了主-客体的相互作用模式, 并利用¹H NMR、紫外吸收光谱法进行了佐证.     

Heterocycles from Pyrazoloylhydroximoyl Chloride: Synthesis of Certain Quinoxaline,Benzothiadiazine, Benzoxadiazine,Quinazolinone, Imidazo[1,2-a]pyridine,Imidazo[1,2-a]pyrimidine,Isoxazole, Pyrazolo[3,4-d]pyridazine and Pyrrolidino[3,4-d]isoxazolin-4,6-dione Derivatives

3-Ethoxycarbonyl-5-methyl-1-(4-methylphenyl)-4-pyrazoloylhydroximoyl chloride (1) reacted with o-phenylenediamine, o-aminothiophenol, o-aminophenol and methyl anthranilate to afford 3-nitrosoquinoxaline, benzothiadiazine, benzoxadiazine, and 3-hydroxyquinazoline, respectively. Imidazo[1,2-a]pyridine, imidazo[1,2-a]pyrimidine and isoxazole derivatives were obtained via the reaction of 1 with 2-aminopyridine, 2-aminopyrimidine and the appropriate active methylene compounds, respectively. Pyrazolo[3,4-d]pyridazines, and pyrrolidino[3,4-d]isoxazolines derivatives were also synthesized. The structures of the newly synthesized compounds were established on the basis of spectral data and alternate synthesis whenever possible.     

Heat-gradient analytical technique for the simultaneous determination of some aromatic amines

A new sensitive analytical technique has been developed for the simultaneous determination of aromatic amines (aniline, p-nitroaniline, m-nitroaniline, o-nitroaniline, 1,3-phenylenediamine, and 1,4-phenylenediamine). It is based on the differential migration of colored derivatives formed by the reaction of diazotized amines with 8-hydroxy quinoline 5-sulphonic acid (FERRON) on a silica gel plate. Quantitative evaluation of amines is made by visual comparison of the intensities of color by spectrophotometry. The Beer’s law, molar absorptivity, and Sandell’s sensitivity have been determined. The effect of the analytical parameters on the migration and analysis have been evaluated. The method is highly reproducible and has been applied to the determination of amines in environmental samples. The text was submitted by the authors in English.     

Complexes of oxovanadium(IV) with cyclic nitrogen-containing ligands

Summary Five complexes were prepared containing VOSO₄ and the ligands 4-aminopyridine (4-APY), 3-aminopyridine (3-APY), 2-aminopyridine (2-APY), 2-aminopyrimidine (2-APYM), and aniline (AN). Complexes of 4-APY and AN did not react with orthophenanthroline (o-phen) and dipyridyl (dipy); the others did react, however, giving similar products. Spectroscopic evidence shows that bonding occurs preferably through an endocyclic nitrogen whenever the ligand possesses more than one type of nitrogen atom.The shift in (VO) upon complexation seems to depend both on the basicity of the ligands as well as on the coordination number of the metal atom. The electronic spectra show two absorptions for the complexes with monodentate ligands and three absorptions for those with bidentate ligands. The former are thought to haveC ₁ symmetry whereas the latter are likely to beC _s species.     

Porous copolymer-based cation exchanger for the off-line preconcentration of aromatic amines from water

Summary A weakly polar porous copolymer and the sulfonic acid cation exchanger based on this copolymer were tested as sorbents for off-line preconcentration of aromatic amines from water. Minicolumns packed with the 1,4-di(methacryloyloxymethyl)naphthalene—divinylbenzene copolymer and the cation exchanger were used for the solid-phase extraction of polar amines. In order to study the sorption properties of these polymeric materials, the recoveries and breakthrough volumes ofp-aminophenol,o, m andp-phenylenediamine, aniline,o andp-anisidine,p-nitroaniline, ando-toluidine were determined.     

Reactions with Naphthoylhydroxlmoyl Chlorides: Synthesis of Derivatives of Isoxazole,Pyrrolidino[3,4-d]isoxazoiin-4,6-dione,lmidazo[1,2-a]pyridine,lmidazo[1,2-a]pyrimidine,Benzotriazine and Benzothiadiazine

Hydroximoyl chlorides 3 react with acrylonitrile, N-arylmaleimide and maleic anhydride to give isoxazolines 5 , pyrrolidino[3,4-d]isoxazolines 8 , and furolidino[3,4-d]isoxazolines 9 , respectively. 3 reacted with 2-aminopyridine, 2-aminopyrimidine, o-phenylenediamine and o-aminothiophenol to yield 3-ni-trosoimidazo[1,2-α]pyridines 20 , 3-nitrosopyrimidines 22 , 3-naphthoyl-1,4-dihydrobenzo-1,2,4-triazines 24 , and 3-naphthoyl-4H-1,3,4-benzothiadiazine 27 , respectively. Compound 3 reacted with benzoylacetonitrile, acetoacetanilide, thiophenol, benzencsulfinic acid in ethanolic sodium ethoxide solution to give the corresponding isoxazoles 12–13 and oximes 16–17 , respectively. The structures of these products were confirmed by elemental analyses, spectral data and, wherever possible, alternative synthesis.     

Synthesis and studies of homopolyamides based on 2,4-bis(6-chlorocarbonyl-2-naphthyloxy)-6-(4-methyl-1-piperazinyl)-s-triazine

Abstract  

Ten homopolyamides have been synthesized by polycondensation of the monomer 2,4-bis(6-chlorocarbonyl-2-naphthyloxy)-6-(4-methyl-1-piperazinyl)-s-triazine and different diamines such as 4,4′-biphenyldiamine, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfonamide, 2,4-diaminotoluene, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, and ethylenediamine. All polyamides were characterized by solubility, density, viscosity measurements, IR, NMR spectroscopy, and thermogravimetric analysis. The products were found to possess high thermal stability.     

Synthesis and Transformations of 2-Hydroxy-2-(benzotriazol-1-yl)-1,4-naphthoquinone

2-Hydroxy-3-(benzotriazol-1-yl)-1,4-naphthoquinone reacts with o-phenylenediamine and 4-chloro-2-aminophenol to give cyclization products: 5-oxo-6-(benzotriazol-1-yl)-5,6H-benzo[a]phenazine and 5-oxo-6-(benzotriazol-1-yl)-10-chlorobenzo[a]phenoxazine; the reaction with aniline yields the quaternary anilinium salt, and benzoyl chloride and benzenesulfonyl chloride acylate the nitrogen atom of the benzotriazolyl moiety.     

The preparation of conducting polyaniline�Csilver and poly(p-phenylenediamine)�Csilver nanocomposites in liquid and frozen reaction mixtures

The oxidation of aniline with silver nitrate in 1?mol?L^?1 acetic acid at 20?°C yielded a composite of two conducting components, polyaniline and silver; the acceleration with 1?mol% of p-phenylenediamine is needed for efficient synthesis. The yield and molecular weight increased when aniline was copolymerized with 10?mol% p-phenylenediamine. Such product displayed metallic conductivity below 180?K and semiconductor type above this temperature. As the result, the conductivity was the same at 100 and 300?K. The oxidation of p-phenylenediamine alone with silver nitrate also produced a conducting composite having the conductivity of 1,750?S cm^?1 despite the assumed nonconductivity of poly(p-phenylenediamine). The present study demonstrates that all oxidations proceeded also in frozen reaction mixtures at ?24?°C, i.e., in the solid state. In most cases, molecular weights of polymer component increased, the conductivity of composites with silver improved, to 2,990?S?cm^?1 for poly(p-phenylenediamine)?Csilver, and remained high after deprotonation with 1?mol?L^?1 ammonium hydroxide.     

Molecular Structure of Phenylphosphine and Its Analogs by Gas-Phase Electron Diffraction and Quantum-Chemical Calculations

The molecular structures of phenylphosphine and its analogs, aniline and phenylarsine, were studied by gas-phase electron diffraction and quantum-chemical methods. The geometry and force constants were calculated at the HF/6-31G and B3LYP/6-31G^* levels of theory. Phenylphosphine and phenylarsine possess a bisector conformation with asymmetric phenyl rings. The main geometric parameters are as follows (r _a): P-C 1.833(6), C-Cav 1.397(1)Å. The structures of molecules like X₂YPh (X = H, F, Cl; Y = N, P, As) were discussed.