SYNTHESIS AND PHOTOPHYSICAL PROPERTIES OF CONJUGATED POLY(9,9-DIALKYLFLUORENOLBENZOBISOXAZOLE)S

A series of new conjugated rigid-rod polymer poly (9, 9-alkyl fluorenolbenzo bisoxazole) s (PBOPFx) containing an fluorene and benzobisoxazole structures were synthesized by 4,6-diamino-1, 3-benzenediol dihydrochloride (DAR) and 9, 9-dialkyl-2, 7-dicarboxyl fluorine, The polymer was characterized by the elemental analysis, H-1-NMR, FTIR, thermogravimetric analysis (TGA) and photoluminescence (PL) spectra. The absorption and photolumineseence spectra of the polymers were also studied. The protonated PBOPFx in methanesulfonic acid solutions exhibits a blue emission with a peak at 466 nm or so. In contrast with that of PBO, the maximal emissions spectra and absorption spectra of PBOF red-shifted due to the introduction of the fluorene group which enhanced effective conjugation of polymer structure unit. In addition, emission spectrum of PBOPFx at 320 nm and 430 nm were compared, the Oxidation-reduction curve is observed, and at last that PBOPFx solution has two conjugated units was verified, but two conjugated units did not show a clear separation, electronic transmission occurred in hybrid, so PBOPFx mostly showed the absorption and emission of the main conjugated unit. Also as a result of existence of alkyl side chains in fluorene unit, the thermal stability of polymers (PBOPFx) is lower than polyphenylene Benzodiazepine oxazoline (PBO) polymer, the initial decomposition temperature is about 350 degrees C but in the respect of dissolved character, PBOPFx has a great improvement, can well dissolved in most organic solvents.