Synthesis and characterization of 1,3,4‐oxadiazole‐containing polyazomethines

Abstract

Novel 1,3,4‐oxadiazole‐containing polyazomethines were synthesized by the polycondensation of diamines, 2,5‐bis (m‐aminophenyl)‐1,3,4‐oxadiazole (BMAO) and 2,5‐bis (p‐aminophenyl)‐1,3,4‐oxadiazole (BPAO), with aromatic dialdehydes, isophthalaldehyde and terephthalaldehyde, in m‐cresol at 20°C. These polymers were yellow to orange in color and had reduced viscosities up to 1.13 dL/g and electric conductivity as high as 10−11−10−12 S cm−1. All the polyazomethines were insoluble in common organic solvents but dissolved in concentrated sulfuric acid. Thermogravimetry showed that thermal degradation started at around 400°C in air and nitrogen atmospheres. Doping with iodine markedly increased the conductivity and produced the black‐colored semiconductive polyazomethines with a maximum conductivity of the order of 10−6 S cm−1. Electronic spectra of the undoped polymers indicated a large bathochromic shift of the absorption maxima due to CN bonds of the monomer diamines (285 nm for BMAO and 315 nm for BPAO). This suggests that π‐electrons of the polymers are extensively delocalized along the main chain.

Liquid crystalline polymers IX Main chain thermotropic poly (azomethine – ether)s containing thiazole moiety linked with polymethylene spacers

“…As mentioned in our previous work [18], the first successful synthesis of high molecular mass, wholly aromatic polyazomethines by the solution polycondensation technique, was that reported by Suematsu et al [3]. This was followed by the work of Saegura et al [20] who synthesized a series of polyazomethines containing heterocyclic moieties. Both groups used m-cresol as a solvent.…”

A silicon-containing polyazomethine and derived metal complexes: synthesis, characterization, and evaluation of the properties

“…), conjugated polyazomethines-containing 1,3,4-oxadiazole rings present the disadvantage of low solubility. [7,9,15] There are some possibilities to improve this behavior of the polyazomethines, one of the approaches consisting in the insertion of the bulky groups or flexible moieties either within the chain or in lateral position obstructing packaging polymer chains. We have previously published a number of studies on the synthesis and study of polyazomethines-containing flexible dimethylsiloxane fragments coming either from amine [16][17][18] or carbonyl [19,20] derivatives and some of their metal complexes.…”

“…The thermooxidative stability or electric conductivity of these polyazomethines are comparable with those of fully aromatic systems or higher. [9] Most of heterocycles are chromophores. One of them, 1,3,4-oxadiazole, for example, proved to confer to the systems in which it is incorporated good resistance in oxidative atmosphere and hydrolytic stability, improved mechanical properties, and blue light emission.…”

Synthesis, characterization, conductivity and antimicrobial study of a novel thermally stable polyphenol containing azomethine group

“…They have drawn the attention of researchers in recent years due to their some properties such as, optoelectronic [1e3], semiconductive [4,5], and photovoltaic [6,7], antimicrobial activities [8] and high thermal stability [8,9].…”