Synthesis and Properties of Two Novel Fluorene-based Derivatives

Two new fluorene derivatives,2,7-bis(2,4-difluorophenyl)-9,9-dioctylfluorene and2,7-bis(4-methoxyphenyl)-9,9-dioctylfluorene were synthesized and characterized by elemental analysis,IR spectra,and NMR spectroscopy.Their optoelectric properties were measured by UVVis absorption spectra and fluorescence spectra.The results show that compound 1and 2have low-energy absorption bands ranging from 300 nm to 330 nm in dichloromethane solution,which can be assigned to theπ-πcharge transfer transitions,with the optical band gap(Eg)3.53 eV and3.32 eV,emission peak 367 nm and 387 nm respectively.The compounds exhibit strong blue photoluminescence under 320 nm excitation wave length at room temperature.The fluorescence quantum yields in CH2Cl2 of compound 1and 2are up to 0.60 and 0.80,respectively.