Synthesis And Properties Of Pyrene And Pyrene Derivatives Containing Boron Aza Atoms

In recent years,replacement of a CC unit with its isoelectronic BN unit can generate novel BN-doped aromatic compounds.Thanks to their unique electronic structure and photophysical properties,BN-doped aromatic compounds have potential applications in biomedicine and materialscience.The dissertation focused on synthesis of BN-doped pyrene-type aromatic compounds,it can be divided mainly into two parts:the first part is investigation of aryls-fused BN-doped pyrenes;the second isexplore the BN-doped pyrenes.We have successfully synthesized these two types of BN-doped 2H-pyrenes,systematically studied their photophysical properties.The details are as follows:In the first part,the key intermediate 5,8-diarylquinoxalines were obtained by Suzuki or Still coupling reaction between 5,8-dibromoquinoxalines,which can be reduced under using different reducing reagent.Electrophilic arene borylation of 5,8-dibromo-1,2,3,4-tetrahydroquinoxaline can deliver the finalaryl-fused BN-doped pyrenes.According to their x-ray structures and theoretical calculations,We found that BN-6-member ring in the target molecular shows weak aromaticity.Their photophysical properties were studied systematically.We found that the absorption and emission spectra red shifted by increasing the size of?-conjugation.We also investigated the potential application of the BN-doped2H-pyenes as fluoride ion sensor,and we found that both of the absorption and emission of the BN-doped 2H-pyenes were inhibited after adding excess F~-.This phenomenon demonstrated that the Lewis acidity of boron atom in the BN-doped 2H-pyenes remain intact.In the second part,we synthesized non-fused BN-doped pyrene using a similar route.According to x-ray structure analysis and theoretical calculations,again,we found that the BN-6-member ring in BN-doped 2H-pyrene compounds have weak aromaticity.In addition,we also studied the photophysical properties of BN-doped 2H-pyenes,which will shed light on the application of BN-doped aromatics in the future.In summary,the thesis focused on the developing BN-doped pyrene-tpye aromaticscompounds.The photophysical properties of the as-synthesized BN-doped pyrenes are systematically investigated.These results will promote the further application of BN-heteroacenes.