Regular Copolyamides. IX. Some Aliphatic Aromatic Copolyoxamides

Abstract

Aromatic/aliphatic regular copolyoxamides were prepared from aromatic diamine-oxamides and aliphatic diacid chlorides of various lengths of methylene groups by solution polymerization. The aromatic diamine oxamides, N,N′-bis(4-aminophenyl)oxamide and N,N′-bis(3-aminophenyl)oxamide were prepared and both were reacted with adipoyl chloride, suberoyl chloride, and sebacoyl chloride to form six new regular copolyoxamides. The polymers formed were soluble in sulfuric acid and also in some polar amide solvents. All copolyoxamides were high melting, with the meta-phenylene copolyoxamides melting from 346 to 373°C with decreasing length of the aliphatic diacid chloride, and the para-phenylene copolyoxamides decomposing prior to melting at near 400°C. The new polymers were characterized by UV spectrophotometry, differential scanning calorimetry, and thermal gravitational analysis.     

Synthesis and characterization of new polyamideimides with a highly flexible soft block

Five new polyamideimides (PAI) were synthesized from five diacid chlorides with preformed imide rings and a telechelic α,ω-diamino-polyoxyethylene (Jeffamine JFA ED600). The diacid chloride monomers could be obtained in high yields (77–92%) from chlorinating the corresponding diacids which were obtained from the reaction of trimellitic anhydride with aromatic diamines (1,4-phenylene diamine; 2,2-bis(4-aminophenyl)methane; 2,2-bis(4-aminophenyl)propane; 4,4′-oxydianiline and 1,1-bis(4-aminophenyl)cyclohexane). The telechelic monomers were characterized by FTIR and ¹H-NMR. After a few preliminary experiments aimed at optimizing the polymerization conditions for particularly poorly soluble diacid chlorides, five new PAI were synthesized with inherent viscosities in the range of 0.35–0.65 dL/g. Their characterization by transmission FTIR and by advanced NMR techniques, including heteronuclear 2D NMR, fully confirmed their chemical structure as shown by the complete assignments of their ¹H and ¹³C-NMR spectra. Compared with other PAI described in the literature, these polymers proved to be much more sensitive towards polar organic solvents even showing significant solubilities in chloroform and tetrahydrofuran. These materials enabled the casting of transparent films which were very tough in the dry state. However, and as further evidenced by a DSC investigation, their phase separation is usually not sufficient to provide a very strong physical crosslinking by the aggregation of the polymer hard blocks. Consequently, their physical crosslinking would have to be significantly improved for preventing the material failure in highly solvating media and open the way for new performances in membrane separation systems. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2873–2889, 1999     

The synthesis and characterization of new metal-free and metallo phthalocyanines substituted with four dithiatetraoxa macrocyclic moieties

New metal-free phthalocyanine (7) fused symmetrically in peripheral positions with four dithiatetraoxa macrocycles, has been synthesized by cyclotetramerization of the isoindolinediimine derivative of macrocyclic 6. Metallophthalocyanine (8) was synthesized by reaction of phthalonitrile derivative (5) with anhydrous nickel(II) chloride. The new compounds were characterized by elemental analysis, ¹H and ¹³C-NMR, IR UV–Vis and mass spectroscopies.     

Polymerization of Phenylacetylene by Molybdenum (V) Chloride Activated by Acetylene Compounds

Abstract

The activating effect of acetylenic compounds for the polymerization of phenylacetylene by molybdenum (V) chloride. The alkyl and aromatic terminal acetylenes were found to activate the MoCl5 for the polymerization of phenylacetylene. The terminal acetylenes having acidic hydrogen (functional group: carboxylic acid, hydroxy) also activate the MoCl5 catalysts. On the other hand, the polymerization of phenylacetylene using MoCl5-acetylenic amines did not proceed.     

The Preparation of Acylselenourea and Selenocarbamate Using Isoselenocyanate

Acyl isoselenocyanates were prepared by a reaction of acyl chloride with KSeCN. The acyl isoselenocyanates formed in situ were ready for further reaction without concentration. N-Acyl selenoureas were obtained by a reaction of acyl isoselenocyanates with amines. The reaction of acyl isoselenocyanates with nucleophiles gave the corresponding selenocarbamate. All the compounds were well characterized by using spectral data, such as ¹³C and ⁷⁷Se NMR and X-ray diffraction.     

Preparation and Characterization of New Optically Active Poly(amide-imide)s from N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic)-bis-L-isoleucine and Aromatic Diamines

Five new optically active aromatic poly(amide-imide)s (PAIs) 5a–e were prepared from a direct polycondensation reaction of a new diacid of N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic)-bis-L-isoleucine 3 with various aromatic diamines 4a–e in a medium consisting of triphenyl phosphite (TPP), calcium chloride (CaCl₂), pyridine (Py) and N-methyl-2-pyrrolidone (NMP). The polycondensation reaction produced a series of novel poly(amid-imide)s 5a–e in quantitative yields with inherent viscosities of 0.39–0.51 dL/g. The resulting polymers were fully characterized by means of ¹H-NMR, FT-IR spectroscopy, elemental analyses, inherent viscosity, solubility test, specific rotation and thermal properties of them were investigated using TGA/DTG and differential scanning calorimeter (DSC). The diacid 4 was synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6- tetracarboxylic dianhydride 1 with L-isoleucine 2 in acetic acid solution.     

Synthesis and Spectroscopic Evaluation of Novel N-, S-, and O-Substituted 1,4-Naphthoquinone Derivatives

Abstract

Novel O- S,O- S,S- N,N- and N,S-substituted naphthoquinone compounds were prepared by reaction of 2,3-dichloro-1,4-naphthoquinone and the corresponding nucleophiles in the presence of chloroform and triethylamine or ethanol solution of Na₂CO₃. The structures of the novel naphthoquinone compounds were characterized by micro analysis, FT-IR, UV/Vis, ¹H NMR, ¹³C NMR, MS, and fluorescence spectroscopy.

GRAPHICAL ABSTRACT      

Aromatic Polyamides of 2,6-Naphthalenedicarboxylic Acid

Wholly aromatic polyamides have been prepared by the interfacial polycondensation of 2,6-naphthalenedicarboxylic acid chloride with m-phenylenediamine. Also, copolyamides with isophthaloyl or terephthaloyl chlorides and the naphthalene diacid chloride were synthesized. The resultant polyamides were amorphous or slightly crystalline as determined by x-ray diffraction, had tensile properties characteristic of hard, strong materials, and were more thermally stable than aromatic polyamides prepared solely from benzene diacid chlorides.     

Pd‐Pt/modified GO as an efficient and selective heterogeneous catalyst for the reduction of nitroaromatic compounds to amino aromatic compounds by the hydrogen source

In this work, different nitroaromatic compounds were successfully reduced to their corresponding aromatic amines with excellent conversion and selectivity in methanol at 50 °C by using Pd‐Pt nanoparticles immobilized on the modified grapheme oxide (m‐GO) and hydrogen as the reducing source. The catalytic efficiency of Pd and Pd‐Pt loading on the modified GO was investigated for the reduction of various nitroaromatic compounds, and the Pd‐Pt/m‐GO system demonstrated the highest conversion and selectivity. The catalyst was characterized by different techniques including FT‐IR, Raman, UV–Vis, XRD, BET, XPS, FESEM, EDS, and TEM. The metal nanoparticles with the size of less than 10 nm were uniformly distributed on the m‐GO. The catalyst could be reused at least five times without losing activity, showing the stability of the catalyst structure. Finally, the efficiency of the prepared catalyst was compared with Pd‐Pt/AC, and Pd‐Pt/GO catalysts.     

Synthesis and physico-analytical studies of some novel ferrocenyl Schiff base derivatives

A series of ferrocenyl Schiff base derivatives was synthesized by condensation reactions of 1,1′-ferrocenedicarboxaldehyde and aromatic amines containing long chain alkyl groups as free ends which were characterized by their physical properties, elemental, FTIR, ¹H NMR, ¹³C NMR spectral and thermal analysis. The thermal behaviour of the synthesized compounds was studied by differential scanning calorimetry (DSC) which revealed that these compounds may exhibit mesomorphic properties. The DSC results of aromatic amines and ferrocenyl Schiff bases were compared to study the effects of structure, i.e. rigid core and terminal chain length, on the phase transition behaviour.     

Photocatalytic Reduction of Nitro Compounds Using TiO2 Photocatalyst by UV and Vis Dye-sensitized Systems

Nitro‐aromatic compounds can be photocatalytically reduced into the corresponding amine‐aromatic compounds using TiO₂ as a photocatalyst in the UV/TiO₂/holes scavenger and Vis/TiO₂/dye‐sensitized systems. In the UV/TiO₂/holes scavenger system, reaction substrate alcohols such as methanol could be used as the holes scavengers, and in the Vis/TiO₂/dye‐sensitized system, substrate alcohols could be oxidized to the corresponding aldehydes with high selectivity. When methanol was used as the holes scavengers and the illumination time was 6 h, 87.2% of p‐nitrotoluene could be photocatalytically reduced into p‐toluidine. In the Vis/TiO₂/dye‐sensitized system, the effect of aromatic alcohols for the photocatalytic reduction of nitrobenzene was better than that of other alcohols. At the same time, aromatic alcohols can be easily oxidized, and the production efficiencies of the corresponding aldehydes were higher than those of other alcohols. The possible reaction mechanisms were also proposed.     

Chelatbildende Enaminoketone I. Synthese von unsymmetrischen Liganden

Syntheses of chelating enaminoketones for a potential use in enrichment or recovery of metals from their aqueous solutions are described. Tridentate ligands were prepared either from aromatic amines, triethoxymethane and cyclic 1,3-dicarbonyl compounds in a one-step synthesis, or from the anilinomethylene compounds obtained by this approach and aliphatic amines. Polymerizable ligands have also been synthesized by reaction with (meth)acryloyl chloride and copolymerized with styrene to yield a chelating polymer.

     

Suitability of ionic liquids as mobile‐phase additives in HPLC with fluorescence and UV detection for the determination of heterocyclic aromatic amines

The effects of several ionic liquids (ILs) as mobile‐phase additives in HPLC with fluorescence and UV–Vis detection for the determination of six heterocyclic aromatic amines were evaluated using two different C₁₈ stationary phases with moderate silanol activity. The studied ILs were 1‐butyl‐3‐methylimidazolium tetrafluoroborate, 1‐hexyl‐3‐methylimidazolium tetrafluoroborate and 1‐methyl‐3‐octylimidazolium tetrafluoroborate. The optical behaviour of heterocyclic aromatic amines in presence of ILs was studied and the silanol‐suppressing potency of ILs was evaluated for the two stationary phases studied. Several chromatographic parameters were evaluated in the presence or absence of ILs, or using triethylamine, the most common mobile‐phase additive. The best results were achieved using 1 mM 1‐butyl‐3‐methylimidazolium tetrafluoroborate as mobile‐phase additive and NovaPak^® column. In these conditions and with 18% of ACN in the mobile phase, analytical performance of the chromatographic methods using fluorescence and UV–Vis were evaluated, obtaining good precision in all cases (RSD lower than 6.6%) and low LOD (0.001–0.147 μg/mL with UV–Vis and 0.001–0.006 ng/mL with fluorescence detection).     

Synthesis of Heterocycles from the Products of Anionic Arylation of Unsaturated Compounds. 7. Products of Haloarylation of Acrylic Acid and Its Esters in the Synthesis of Benzo[b]thiophene Derivatives

3-Chloro-2-chlorocarbonylbenzo[b]thiophenes were obtained on oxidation of Meerwein reaction products, viz. 3-aryl-2-halopropionic acids and their esters, with thionyl chloride in the presence of N-benzyl-N-methylmorpholinium chloride. Disubstituted thioureas were synthesized by the reaction of these compounds with ammonium thiocyanate and aromatic amines, and were cyclized by interaction with iodoacetic acid with the formation of 4-thiazolidinone derivatives. The same cyclization in the presence of aromatic aldehydes leads to the formation of the corresponding 5-arylidene-substituted 4-thiazolidinones.     

New organotin(IV) complexes with N(4)-methylthiosemicarbazone derivatives prepared from 2,3-dihydroxybenzaldehyde and 2-hydroxy-5-methylbenzaldehyde: synthesis,characterization, and cytotoxic activity

Abstract

The N(4)-methylthiosemicarbazone derivatives H₂DDMT (1) and H₂DMMT (2) have been prepared from the reaction of 4-methylthiosemicarbazide with 2,3-dihydroxybenzaldehyde and 2-hydroxy-5-methylbenzaldehyde, respectively. Six new organotin(IV) complexes, [MeSnCl(DDMT)] (3), [BuSnCl(DDMT)] (4), [PhSnCl(DDMT)] (5), [MeSnCl(DMMT)] (6), [BuSnCl(DMMT)] (7), and [PhSnCl(DMMT)] (8) have been synthesized by direct reaction of corresponding organotin(IV) chloride(s) with these ligands. The ligands and their compounds have been characterized by elemental analysis, molar conductivity, UV–Vis, FT-IR, and NMR (¹H, ¹³C, and ¹¹⁹Sn) spectroscopy. The molecular structures of 1 and 2 were determined by X-ray crystallography. Spectroscopic data suggested that the ligands were coordinated to tin(IV) as dinegative tridentate via phenoxide-O, azomethine-N, and thiolate-S atoms. The crystal structures revealed that the ligands exist in thione form in the solid state. In vitro cytotoxicity assays were carried out for all the compounds against MCF-7 cancer cell line. The results have shown that different organotin(IV) groups showed characteristic differences in their biological activity.     

Studies on the Synthesis and Perporties of Ethyl-N-Alkylphosphoro(Thioureido)Thioates

Abstract

O-Ethyl-N-alkylphosphoro(thioureido)thioates(II) were synthesized by the addition of O-ethyl-N-alkylphosphor-isothiocyanatidothioates(I) with corresponding alkyl or aryl amines, in which R=C¹, -C₃, R¹, R²=H, alkyl or aryl. Their structures were confirmed by IR, ¹H NMR, MS and elemental analysis. The results of bioassay showed that they had fairly good fungicidal and herbicidal activities. When II(R¹=H,R²=i-Pr,Ph,aryl etc.) reacted with chloroacetyl chloride, the compounds III were given.     

Synthesis,reactions, and antioxidant activity of 3-(pyrrol-1-yl)-4,6-dimethyl selenolo[2,3-b]pyridine derivatives

Ethyl 4,6-dimethyl-3-(pyrrol-1-yl) selenolo[2,3-b]pyridine-2-carboxylate (2) was synthesized by the reaction of previously prepared ethyl 3-amino-4,6-dimethyl selenolo[2,3-b]pyridine-2-carboxylate (1) with 2,5-dimethoxytetrahydrofuran in acetic acid. The pyrrolyl ester (2) was converted into the corresponding carbohydrazide 3 which reacted with acetyl acetone, aromatic aldehydes, carbon disulfide in pyridine, and sodium nitrite to afford the corresponding dimethyl pyrazolyl 4, arylidene carbohydrazides 5a–d, oxadiazolyl thiole 6, and caboazide compound 8, respectively. The carboazide 8 reacted with different alcohols and amines to give the corresponding carbamates 9a–c and the aryl urea derivatives 10a–d. Heating of carboazide 8 in dry xylene afforded the pyridoselenolo-pyrrolopyrazinone 11. The latter compound was used as a versatile starting precursor for synthesis of other pyridoselenolo-pyrrolopyrazine compounds. The newly synthesized compounds and their derivatives were characterized by elemental analysis and spectroscopy (IR, ¹H-NMR, and mass spectra). Some of the newly synthesized pyrrolyl selenolopyridine compounds showed remarkable antioxidant activity compared to ascorbic acid.     

COMPARED PROPERTIES OF FLUORINATED HETEROCYCLIC COPOLYIMIDES

Various new fluorinated heterocyclic copolyimides have been synthesized by a polycondensation reaction of a diacid chloride containing imide, hexafluoroisopropylidene and methylene groups with aromatic or heteroaromatic diamines containing preformed phenylquinoxaline or 1,3,4-oxadiazole rings. Other fluorinated heterocyclic copolyimides have been prepared by a polycondensation reaction of the same diacid chloride with aromatic dihydrazides, bis(o-hydroxy-amine)s or a bis(o-carboxy-amine), resulting in intermediate polyhydrazides, poly(o-hydroxy-amide)s or poly(o-carboxy-amide), respectively, which were futher cyclodehydrated to the corresponding polyoxadia zole-imide, polybenzoxazole-imide or polybenzoxazinone-imide structure. These polymers showed good solubility in polar amidic solvents, such as N-methylpyrrolidinone (NMP) and dimethylformamide (DMF), and even in less polar liquids, like tetrahydrofurane or pyridine, except for those compounds containing benzoxazole rings which were less soluble, only on heating in NMP or DMF. The weight average molecular weight measured for tetrahydrofurane-fully-soluble polymers are in the range of 12800–26700 and the polydispersity is in the range of 2–5. All these polymers exhibited good thermal stability, with decomposition temperature being above 350°C, although somewhat lower than that of related polymers prepared by using fully aromatic diacid chlorides instead of the present ones containing methylene units. The glass transition temperature is in the range of 200–300°C. The dielectric constant measured for polymer films is in the range of 3.3–3.7. Tensile strength is in the range of 35–70 MPa, elongation to break between 30–40% and tensile modulus in the range of 170–330 MPa. A study of the relation between conformational parameters and properties of some of these polymers has been carried out by using the Monte Carlo method with an allowance for hindered rotation, and the values were compared with the experimental data and discussed in relation with the rigidity of the chains. The present polymers are potential candidates for use as high performance materials.     

Augusto Sirigu (1939–2007)

Two series of novel symmetrical azomethines prepared by the condensation of 4,4′-(butane-1,4-diylbis(oxy))bis(butane-4,1-diyl)bis(4-aminobenzoate) (PBBA470) and 5,10,15,20,25,30,35,40,45,50,55,60-dodecaoxatetrahexacontane-1,64-diylbis(4-aminobenzoate) (PBBA 1200) with a range of aldehydes have been characterised by ¹H and ¹³C nuclear magnetic resonance, Fourier transform infrared and UV–Vis spectroscopy. Current–voltage measurements were performed using a device comprising indium–tin oxide/compound/Alq₃/Al. The effect of rod length and the nature of the terminal chains on the thermal and mesomorphic behaviour of these materials were investigated by differential scanning calorimetry, polarising optical microscopy and wide- and small-angle X-ray diffraction. Additionally, the compounds were studied using various atomic force microscopy techniques, including mode and phase imaging, and measurements based on local contrast force–distance curves and roughness, together with skew and kurtosis, are presented.