Effect of Higher Nonbenzenoids in Optical Properties of Dihydropyrene-Thiophene and Dihydropyrene-Phenylenevinylene Copolymers

摘要

One dihydropyrene-thiophene and a series of three dihydropyrene-phenylenevinylene copolymers were synthesized in this work. The core dihydropyrene unit was shown to remain intact in the polymer backbone by H-1 NMR studies. Thermal studies indicated higher stability of the dihydropyrene unit in the copolymers compared with the parent molecule, with one of the dihydropyrene-phenylenevinylene copolymers exhibited a single-step onset degradation temperature at 400 degrees C. Extended conjugation effect in the copolymers was evident based on spectroscopic analysis despite a mismatch of macrocyclic dihydropyrene units and small conjugation partners (thiophene and phenylenevinylene). The copolymers exhibited relatively small bandgaps. All four copolymers exhibit blue light emission in photoluminescence studies. Their emission spectra are essentially identical, suggesting that their emission properties were dominated by the dihydropyrene chromophore but independent of the spacer group (thiophene or phenylenevinylene).