Synthesis And Orientation Of Functionaiized Discotic Hexa-peri-hexabenzocoronene Derivatives

Discotic liquid crystal molecules (DLCs) commonly consist of rigidaromatic cores in the center and flexible aliphatic chains peripherally. DLCscould self-organize into one-dimension column by the strong π-π interactionbetween the adjacent aromatic nucleus which provides channels for thecharge carrier. The peripheral flexible chains mobility and the solubility.Furthermore, at the same time also provide insulating protection to avoid theescape of the charge carrier. Therefore, discotic liquid crystal molecules havea good prospect in the manufacture of organic optoelectronic devices, such asorganic field effect transistors (OFET), organic photovoltaic devices (OPV),organic light-emitting diode (OLED) and other molecular electronic devices.DLCs will be the very suitable materials in the application in optoelectronicdevices by low-cost ways such as dipoing or printing if the solubility isexcellent.Recent studies show that the liquid crystal columnar phase formed fromhexabenzocoronene(HBCs) has the ideal carrier mobility. However, how toorientate on matrix and form long-rang order has been become a seriousproblem for its application in optoelectronic devices. In this paper, consideringthe low solubility of hexabenzocoronene(HBCs), swallow-tailed side-chainsand terminal fluorine atoms were introduced into periphery of aromatic nucleus,which is expected to change the liquid crystal properties of the molecules tostudy the relationship of orientation between molecules and matrix. While thebromine atoms were also designed to introduce into the periphery of thehexabenzocoronene(HBCs) so as to obtain specific molecules with kinds ofactive functional groups（mercapto、amino、vinyl and epoxy group）which canmake the molecules anchored to specific substrates so as to allow us to furtherexplore the formation of long-range order of discotic liquid crystals.The main contents of this paper are shown below: In part one, hexabenzocoronene(HBCs) with swallow-tailedfluorinated-alkoxy chains were designed and of which the mesomorphism wasalso studied. Precursor, hexaphenylbenzene(HPC), was synthesized bycyclotrimerization reaction and then oxidative cyclization dehydrogenated tohexabenzocoronene(HBCs) with anhydrous FeCl3.In part two, a series of HBCs with different functionalized groups such asmercapto、 amino、 vinyl and epoxy were designed. the precursorhexaphenylbenzene(HPC) functionalized with bromine atoms was synthesizedvia Diels-Alder reaction, and the oxidant system FeCl3/CH3NO2wasemployed for oxidative cyclization dehydrogenation reaction. Deep reactionshave restricted by urgent time.