Synthesis And Properties Of Fluorene-Based Strain Grid Materials

Organic strain semiconductor materials have many unique chemical properties and potential applications due to the strain in their structure.The research on them has been one of the hot spots in the field of organic chemistry.At present,the more reported strained organic semiconductor materials are CPP molecules and CPP derivatives with“8-fon”structure.However,due to the strongly strain energy inside CPP molecules and their highly complex structure,the synthesis and research of such materials are still challenging.In order to enrich the types of organic strain semiconductor materials,this paper successfully synthesized high-strain fluorene-based nanogrid aromatic hydrocarbon（Fluorene-Grid）materials with"bow"structure and"cross"structure based on the clear vertex and superior scalability characteristics of H-type fluorene-based materials in our group,which laid a solid foundation for the construction of a new type of high-strain Fluorene-Grid.Combined with the theoretical calculation of high-strain fluorenia materials and on the basis of synthesis within our group,this paper systematically studies the synthesis and application of the strain Fluorene-Grid,and the related work will be carried out from the following three aspects.1.Different from the CPP molecules of the all-benzene ring and the CPP derivatives with the"8-fon"structure,the chapter two is based on the results of theoretical calculation,subsequently the strain Fluorene-Grid CPFDS with the"bow"structure is designed and synthesized.Firstly,the strain energy of the CPFDS is 30.87 kcal/mol through theoretical calculation.Secondly,Suzuki coupling reaction was used in the experimental process,and the"I₂-V synthon"was combined with DBPFDS of diaryl fluorene material at a concentration of 30 mmol/L to successfully obtain the precursor CPFDS-TESO（yield of 11.94%）.Finally,the strain Fluorene-Grid CPFDS with"bow"structure was successfully prepared by reducing aromatization（yield of 28.5%）.Linear molecules LPFS were prepared by the same strategy.In CHCl₃ solution,the photoluminescence quantum efficiencies（PLQY）of strain Fluorene-Grid CPFDS and linear molecule LPFS are 75%and 16%respectively.The experimental results show that the"Gridarenes Effect"is conducive to the enhancement of the luminescence characteristics of the material.2.Based on the chapter two,the chapter three designed and synthesized a strain Spiral-Grid CDPFS with a"cross-type"structure.And its ring strain energy is 45.86 kcal/mol,which is 1.5 times that of strain Fluorene-Grid CPFDS.Firstly,the Spiral-Grid precursor CDPFS-TESO（yield of 8.5%）was successfully synthesized by combining"I₂-V synthon"with fluorene-based material DB-H of higher rigid strength using the Suzuki coupling reaction.Subsequently,CDPFS-TESO was reduced to aromatization to obtain the target product CDPFS（yield of 43.81%）.In CHCl₃ solution,the PLQY value of Spiral-Grid CDPFS is 88%.The results show that the greater of the strain energy in the strain Fluorene-Grid system of this paper,the more conducive to the improvement of photoluminescence quantum efficiency.3.In Chapter 4,the synthesized Fluorene-Grid CPFDS molecule,linear molecule LPFS and Spiral-Grid CDPFS molecule are used as single component charge trapping layer,an Organic Field Effect Transistors（OFET）memory device based on pentaphenyl was prepared.Preliminary experimental results show that in this thesis:CDPFS molecular memory devices with higher strain were found to have a lower threshold voltage.