Design,Synthesis And Properties Of Furan-embedded Fused Twistacenes

The construction of new organic semiconductors with regular structure and controllable properties and their optoelectronic properties have been widely concerned by scientists in recent years.It is a technical challenge for synthesizers,and it also provides material support and selection for device workers.Therefore,this field has attracted much attention of scientists.For example,in the field of electroluminescence and nonlinear optics,devices based on organic materials and their performance have made breakthroughs.Compared with the acene molecule,the twistacenes molecule can effectively inhibit the ?-stacking of molecules in a solid state,and the molecules maintain good photoelectric properties.However,if such molecules accumulate to a certain length,the stability of the molecule is greatly reduced.To this end,the introduction of oxygen heterocycles such as furan and pyran into the skeleton of distorted benzobenzene can further improve the solubility,antioxidant capacity and electron transport ability of the molecule,so that the constructed molecule may have unique properties in non-linear optics and electroluminescence.In line with this idea,we have carried out relevant work,the main research contents are as follows:(1)Twisted acene 3 modified with fluorophenyl,methoxyphenyl and triphenylamine alkynyl groups and its cyclized furan-benzobenzene derivative 5/D5 c were synthesized by Sonogashira reaction and iodine cyclization reaction.Based on the comprehensive characterization of the molecules,the effects of different substituents on the spatial arrangement and photoelectric properties of the compounds were investigated.The third-order nonlinear optical properties of intermediate molecule 3 and cyclic product 5/D5 c were studied by Z-scan technique,and the effect of introducing furan ring on the activity of molecular TPA was investigated.Twisted acene 3 shows two-photon absorption.The TPA cross section of cyclized furan-benzo 5a/D5 c is in the range of 561-1464 GM,and the TPA cross section of cyclized furan-benzo 5a/D5 c is 5732 GM,which is obviously higher than that of cyclized furan-benzo 5a and 5b.It can be seen that the introduction of furan ring is helpful to enhance TPA activity.In addition,the devices fabricated with molecular 5a and D5 c as luminescent layers show bright blue and green electroluminescence respectively.(2)Symmetrical and asymmetrical pyrene/phenanthrofuran modified anthracene derivatives were designed and synthesized.Their structure were proved to be correct by NMR and MALDI-TOF/HR mass spectrometry.Phenanthrene [9,10-b] benzofuran 11,14 and pyrene [4,5-b] benzofuran modified anthracene derivative compound 16 emit strong blue light in solution and have good thermal stability.After the compound 14 or 16 is evaporated,the electronic device prepared as a light-emitting layer can emit white light.This accidental discovery provides new insights into the design and synthesis of fused-ring furan functionalized molecules and the development of their electroluminescent properties.(3)On the basis of the previous work,we designed and synthesized pyran or aza-heterocyclic embedded pyrene/naphthalene modified twisted benzobenzene molecules.The structure of the molecule was confirmed by infrared spectroscopy,NMR spectroscopy,MALDI-TOF/HR mass spectrometry and X-ray single crystal diffraction.Ultraviolet-visible absorption spectra and fluorescence spectra show that these molecules can emit blue fluorescence in solution.In addition,the electrical and thermal properties of the molecule were characterized by cyclic voltammetry and TGA.It is noticed that the electron-donating ability of the molecule is greatly enhanced after the introduction of nitrogen heterocycles.Therefore,a new TADF material is constructed by connecting molecule 21 with the receptor molecule.Its basic properties and electroluminescent properties are being characterized.