Quinoxaline-Containing PAEs

As with several PAEH, PAE containing quinoxaline units were prepared by two different approaches. One route involved the reaction of an aromatic bis(fluoroquinoxaline) compound with various bisphenolates as depicted in Eq. (1) [12]. The quinoxaline unit as with many other heterocyclic units was... 

The second synthetic route to PAE containing quinoxaline units involved the reaction of an aromatic dihydroxy quinoxaline or aromatic bis(hydroxy-quinoxaline) with activated aromatic difluoro compounds (Eq. (3)) [15]. The dihydroxy quinoxaline and bis(hydroxyquinoxaline) monomers were readily prepared from the condensation of 1,2-diaminobenzene with 4,4 -dihydroxyben-zil and aromatic bis(o-diamines) with 4-hydroxybenzil, respectively. The Tgs of a series of PAE containing quinoxaline units are presented in Tables 3 and 4. For these polymers, the trend for the Tg is sulfone > carbonyl > terephthaloyl-> isophthaloyl. This trend holds for most polymer families when polymers of similar molecular weights are compared. Several polyphenylquinoxalines of the same chemical structure as those in Table 3 were also prepared by the poly-... 

Most nitrogen-containing heterocycles (e.g., pyridine, pyrimidine, pyrazine, quinoline, quinoxaline, or benzothiodiazole) are electron deficient. If these heterocycles are introduced into PAEs, polymers with... 

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