Syntheses And Semiconducting Properties Of Novel T-shaped NBN-Embedded Heteroacene Derivatives

Polycyclic aromatic hydrocarbons(PAHs)exhibit great prospect in applications of organic electronic devices due to their substantial semiconducting properties resulting from tunable geometric and electronic structures via various modifications.Incorporation of heteroatoms into PAH’s backbone enables remarkable improvements in the molecular stability,optoelectronic properties and self-assembly behaviors.In this dissertation,starting from the formation of a key intermediate brominated dibenzophenalene with NBN-embedded zigzag edge,various functional groups were introduced to afford a series of T-shaped NBN-embedded dibenzophenalene derivatives.The solid structures,optical properties and electrochemistry behaviors of these molecules were systematically studied and their potential in applications of electroluminescent device was explored.First,through the stoichiometric control of the equivalent of4-aminophenylboronic acid pinacol ester in a palladium-catalyzed coupling reaction with mesotribromobenzene,a key intermediate of brominated benzene in which two meta positions are substituted by aniline groups was obtained.Then,the brominated nitrogen-boron-nitrogen-embedded dibenzophenalene derivative NBN-Br was afforded in an electrophilic reaction with boron tribromide,in which the boron atom was located at the para position of the bromine substituent.Second,different electron-donating functional groups were attached at the B-para position of NBN-Br through transition-metal-catalyzed cross-coupling reactions to afford a series of T-shaped π-extended derivatives NBN-Fns(NBN-Fn,Fn: phenyl(Ph),2-thiphenyl(Th),9-anthryl(An),triphenylamine(TPA),3,6-bis(tert-butyl)carbazole(Cz)).The effects of electron-donating functional groups on the molecules are systematically evaluated in terms of single crystal structure,photophysical properties and electrochemistry behaviors,demonstrating their strong blue emission character.Such aromatics were employed as emitting layers in organic light-emitting diodes(OLEDs),exhibiting relatively pure blue light with CIE(0.16,0.12).Finally,as an extension of the above work,electron-withdrawing groups were introduced into the skeleton to afford T-shaped molecules with donor(D)-acceptor(A)structures using nitrogen-boron-nitrogen-embedded dibenzophenalene as the electron acceptor.The photophysical properties and electrochemical behaviors of these molecules were preliminarily explored.