High glass transitions and fluorescence of novel organosoluble poly(arylene ether)s containing kink noncoplanar heterocyclic structures

A novel unsymmetrical and kink noncoplanar heterocyclic bisphenol-like monomer, 4-(4-hydroxynaphthalenyl)phthalazin-1-one (2), was synthesized in a two-step reaction starting from 1-naphthol and phthalic anhydride via Friedel-Crafts acylation reaction and cyclization with hydrazine hydrate. Two heterocyclic poly(arylene ether)s were prepared conveniently from monomer 2 and two activated dihalide monomers by a N-C coupling reaction. The polycondensation proceeded quantitatively in N,N-dimethylacetamide in the presence of anhydrous potassium carbonate and afford the polymers with inherent viscosities of 0.46 and 0.34 dL/g. Thermal analysis showed that the polymers had excellent thermal properties. The glass transition temperatures were 277 degrees C and 316 degrees C respectively, and the temperatures of 5% weight loss were all above 500 degrees C in nitrogen atmosphere. The unsymmetrical and kink noncoplanar structures of the polymers chains could disturb interchain and intrachain interactions and make them amorphous and readily soluble in polar, aprotic solvents. The dilute solution of the polymers in chloroform showed strong optical absorption in ultraviolet region, and exhibited violet-blue fluorescence with emission maxima at 400-470 nm.