Study On Synthesis And Properties Of Organoboron Compounds Based On Carbazole

A series of boron-containing π-conjugated compounds have been synthesized by the introduction of carbazole group and dimesitylboron group into one molecular structure. The structures of the compounds were characterized by1H NMR,13C NMR, elemental analysis and mass spectrometry. In addition, their photophysical, thermal, electrochemical, sensing and electroluminescence properties were investigated by experimental methods and theoretical calculations.1. Carbazole dimer was synthesized by McMurry coupling reaction with carbazole as a raw material. Then, a novel boron-containing π-conjugated compound A was synthesized by the introduction of dimesitylboron groups at the3,3’-positions of a carbazole dimer. Its photophysical and sensing properties were investigated by absorption spectrum, emission spectra and theoretical calculations. The compound possesses high fluorescence quantum yields. In addition, the compound is a sensitive fluorescence sensor with remarkable color changes. The mechanism could be confirmed through frontier orbitals of the compounds A and A·F22-. We think the complexation of the boron groups with fluoride ion, inhibited the intramolecular charge transfer from the carbazole dimer to the boron side chains, causing changes in fluorescence spectrum.2. A dendritic organic conjugated compound B1was readily prepared by C-N coupling reaction, subsequent bromination and lithiation with t-BuLi. The compound exhibits a strong green fluorescence both in nanoparticles and solid state. In addition, the compound possesses aggregation induced ratiometric fluorescence phenomenon, therefore, photophysical property and AIEE behavior of the nanoparticles of the compound were investigated. Nanoparticles with a diameter of about50nm are clearly observed by SEM and TEM. The unique AIEE phenomenon with ratiometric fluorescence changes and remarkable color change has never been reported. This ratiometric fluorescence change is probably attributed to the intermolecular donor-acceptor interactions which could induce the isolated molecules into staircase or double-string chain arrangements.3. A star-shaped organic conjugated compound was readily prepared by C-N coupling reaction, subsequent bromination with NBS and lithiation with t-BuLi and dimesitylboron fluoride. Its photophysical, thermodynamic, electrochemical and electroluminescence properties were investigated. The results showed that the compound is an outstanding host material, which possesses excellent thermal and electrochemical stability, high fluorescence quantum yields (Φmax=0.95) and high triplet energy (2.95eV). Red and green phosphorescent organic light-emitting diodes were fabricated by using osmium complex and iridium complex as guest materials. The devices showed pure red and green light-emitting and relative good device performances.