Synthesis And Properties Of Bis-BN Dihydropyrene And Its Derivatives

Embedding with heteroatoms,especially main group element,into polycyclic aromatic hydrocarbons(PAHs)is an effective way to alter their structural and electronic properties.In recent years,the replacement of CC double bonds in PAHs with BN bond has become an effective way to construct novel BN-doped PAHs(abbreviated as BN-PAHs).Because of the isoelectronic relationship between BN bond and CC double bonds.BN-PAHs have been found having new electronic structures and photophysical properties.As a result,BN-PAHs showed potential applications in various fields,such as biomedical research,pharmaceutical chemistry,materials chemistry,catalysis and organic synthesis.The research of the thesis can be divided into three parts: The first part is mainly on the design,synthesis and properties of non-fused Bis-BN-doped dihydropyrenes;And the second part is on the synthesis and properties of aryl-fused Bis-BN-doped dihydropyrenes;The third part is focusing on the BN-PAHs bearing a 1,4-azaborine subunit.We successfully synthesized the three types of BN-PAHs,and we investigated their photophysical properties in detail.The details are as follows:In the first part,we successfully synthesized bis-BN anthracenes using Stille cross coupling and Friedel-Craft borylation as the key steps,however with low yield of the final borylation step.By introducing the ethylene group between the two nitrogen atoms,the yield of the final borylation step increase a lot.As a result,the bis-BN dihydropyrene was obtained in good yield.Subsequently,we found the bromination went smoothly to generate the brominated bis-BN dihydropyrenes.We also prepared a series of bis-BN dihydropyrenes by metal catalyzed Suzuki or Heck cross coupling reaction.Furthermore,some of the key compounds were characterized by single X-ray analysis.Moreover,we investigated the photophysical properties of these bis-BN dihydropyrenes.In the second part,we designed and synthesized several pyrrole/indole fused bis-BN dihydropyrene.During the synthesis,we took an effort to optimize the key Ullmann cross coupling step.Using the optimized Ullmann cross coupling condition,the key intermediate was obtained in good yield,followed by reduction/borylation sequence,delivering the target pyrrole/indole fused bis-BN dihydropyrenes.In addition,we investigated the photophysical properties of these bis-BN dihydropyrenes.In the third part,the BN-PAHs with a 1,4-azaborine subunit were designed and synthesized.The BN-PAHs are fully characterized,and some of structures are confirmed by single X-ray analysis.Furthermore,we prepared theirs analogue with a1,2-azaborine subunit.The direct comparison of the photophysical properties of BN-PAHs with a 1,4-azaborine and 1,2-azaborines unit were carried out.We found the both of the absorption and emission spectra of the BN-PAHs with a 1,4-azaborine subunit are red shifted compared to their 1,2-azaborine analogues.In a word,we have successfully synthesized and characterized three types of bis-BN dihydropyrenes,and studied their photophysical in details.These studies will enrich the family of the BN-PAHs.These results will pave a way for the further application of BN-PAHs.