Design,Synthesis,Single Crystal Analyses And Optoelectronic Properties Of Acenes Containing Five-membered Rings

Acenes and their derivatives have received more attention owing to their excellent optoelectronic properties,which could be used as active layers in organic electronics such as organic field-effect transistors（OFET）,organic light emitting diodes（OLEDs）,solar cells and nonlinear optics et al.The larger acenes usually encountered some disadvantages such as sensitive to oxygen and light,ease of dimerization.Thus,in this thesis,the five-membered rings were introduced to the parent acene building blocks.More importantly,the as-formed molecules show excellent stability against light and oxygen.In addition,their ciorresponding optoelectronic,electrochemical and thermal properties were investigated in detail.The obtained compounds could be utilized as active layers for organic electronics.1 Four novel unsymmetrical twistacene analogues were synthesized in a palladium-promoted cross-coupling reaction and fully characterized,where five-membered ring was embedded into the main skeleton in these molecules.The formed all-carbon compounds appreciate a series of promising photophysical properties such as good thermal stability and photostability than those of acenes consisting of all six-membered rings.All of them emitted strong solution fluorescence covered a wide range from cyan to yellow.In addition,the nonlinear optical properties were further investigated through the top-hat Z-scan technique at 515 nm,which indicates that all of them presented excellent third-order nonlinear absorption effects.2 Two novel twistacenes Py SP and PyDP have been successfully synthesized,which was confirmed by ¹H NMR,¹³C NMR and MALDI-TOF spectroscopy.The optoelectronic properties and thermal behavior were investigated through UV-vis absorption,fluorescence spectra,cyclic voltammetric method and TGA.Both of them emitted strong blue and yellow light in organic solvents,respectively.The white organic light emitting diodes based on them were fabricated that showed promising performance.3 A novel two-dimensional bisacene DMAT has been synthesized and characterized by ¹H NMR and mass spectroscopy.The single crystal was obtained from slowly evaporation of a mixture of dichloromethane/methanol solution,where the parent skeleton was a plane and the lateral 2,4,6-methylphenyl unit bent out of this plane.This configuration can suppress the π-π stacking interaction to a certain extent.The as-formed compound emitted strong red fluorescence.In addition,the electrochemical behavior,thermal and self-assembly properties were also investigated.4 A series of five-membered ring functionalized decacenes PyPA,PyPH and Py PN,have been successfully synthesized,which was confirmed by ¹H NMR,¹³C NMR,MALDI-TOF spectroscopy.The optical properties were measured by UV-Vis absorption spectra.