Synthesis and identification of organosoluble polyimides: thermal, photophysical and chemiluminescence properties

Novel fluorescent polyimides (PIs) were prepared from a new diamine, 4-(4-(4-amino-2-(4,5-diphenyl-1H-imidazol-2-yl) phenoxy) phenoxy)-3-(4,5-diphenyl-1H-imidazol-2-yl) benzenamine, and three tetracarboxylic dianhydrides. The new symmetrical diamine was successfully synthesized by the nucleophilic substitution reaction of hydroquinone with 2-(2-chloro-5-nitrophenyl)-4, 5-diphenyl-1H-imidazole (I). The PIs synthesized here are amorphous and soluble in polar aprotic solvents and demonstrate the ability to form films; their inherent viscosities ranged from 43 to 82 ml g(-1). The PIs had suitable thermal stability and relatively high T-g values (245-274 degrees C), 10% weight loss temperatures in excess of 500 degrees C and char yields at 600 degrees C in air up to 62%. The PIs show emission in the solid state and in dilute (0.20 g per 100 ml) N,N-dimethyl acetamide solution at 431-464nm with photoluminescence (PL) quantum yields in the range of 11-25%. The chemiluminescence activity of PIs in the presence of peroxyoxalate was also investigated. Polymer Journal (2010) 42, 648-656; doi: 10.1038/pj.2010.57; published online 30 June 2010