Linear And Macrocyclic ?-Conjugated Molecules On The Basis Of Syn-BN-embedded Polycyclic Aromatic Hydrocarbons

Numerous acenes have attracted considerable attention for their rich electronic properties applicable in various electronic devices such as organic field-effect transistors and organic light-emitting diodes(OLEDs).Replacement of C=C double bonds with isoelectronic and isosteric B–N units in the molecular backbones,similar geometric structures but substantially different electronic structures as associated with the polarization of B–N fragment as compared with their all-carbon analogues.A series of novel BN-heteroacenes and macrocycles were successfully synthesized and structure-property relationships are discussed.The dissertation includes:(1).We give a brief introduction of the background of syn/anti heteroacenes and PAHs embedded with the isoelectronic B-N unit of C=C unit.(2).we successfully designed and synthesized a new family of angular BNheteroacenes,featuring syn-structures that provide them with unique molecular arrangements in the solid state,and significantly improved their photophysical properties in comparison with their anti-isomers.These syn-BN-heteroacenes were used as dopant-free light-emitting host materials to fabricate blue OLED devices that demonstrated favorable performance including a low starting potential without optimization.(3).Upon bromination of the resulting angular BN-heteroacenes,di-brominated intermediates were synthesized in high yields.Then we synthesized a new family of angular BN-heteroacenes derivates by Suzuki or Sonogashira cross-coupling reaction.The optical and electronic properties have been well tuned by coupling different functional groups into the main backbones.(4).Design and synthesis of new type of size-and shape-persistent conjugated macrocycles have attracted considerable interest all the time.In chapter 4,the important building block of dicarbonyl BN-heteroacenes were prepared through direct Vilsmeier–Haack formylation in yield around 60%.By Mc Murry reaction through intermolecular dimerization by reductive coupling of four carbonyl groups,we report the first design and synthesis of shape-persistent and circularly conjugated cyclothiophenes containing four BN units in the backbone.The characterization analysis BN-macrocycles showed interesting electronic property and packing pattern in the crystalline state.BNcontaining macrocycles enable colorimetric and fluorometric dual channel detection of fluoride ions through binding to the Lewis acid boron atom of the BN moiety in high selectivity and sensitivity,especially the macrocycle coordinated with fluoride ions could be oxided by O2 to produce radical cation.The mechanism was also proved by theoretical calculations based on density functional theory.These results showed the BN-macrocycles could be used as potential sensor for multiple ions.