On-surface Synthesis of Multiple Non-benzenoid Carbohelicenes Fused with Fluorene Unit(s)  

作　　者：Wei Xiong Xi Geng Jianchen Lu Gefei Niu Boyu Fu Yi Zhang Shicheng Li Yuhang Yang Nianqiang Li Lei Gao Jinming Cai 

机构地区：[1]Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650093,China [2]Faculty of Science,Kunming University of Science and Technology,Kunming,Yunnan 650093,China [3]Southwest United Graduate School,Kunming,Yunnan 650093,China

出　　处：《Chinese Journal of Chemistry》2024年第22期2811-2817,共7页中国化学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.62271238,22372074,62301240);Yunnan Fundamental Research Projects(Nos.202201AT070078,202201BE070001-009 and 202301AW070017);the Major Basic Research Project of Science and Technology of Yunnan(202302AG050007);Yunnan Innovation Team of Graphene Mechanism Research and Application Industrialization(202305AS350017);Graphene Application and Engineering Research Centre of Education Department of Yunnan Providence(KKPP202351001);the Analysis and Testing Foundation of KUST(2021T20170056).

摘　　要：Carbohelicenes have garnered considerable attention for their inherent chirality and structural flexibility.Increasing multi-helicity and incorporating non-six-membered rings to substitute benzenoid rings within helicenes are effective strategies for introducing unique photoelectric properties.Despite the disclosure of numerous helicenes,the inaccessible precursors and the lack of synthetic routes pose a challenge in achieving desired helicene structures fused with non-benzenoid rings.Herein,we report the synthesis of multiple non-benzenoid carbohelicenes fused with fluorene unit(s)through intramolecular cyclodehydrogenation of 9,10-di(naphthalen-1-yl)anthracene on Au(111)surface.Two potential cyclodehydrogenation manners between naphthyl and anthracene lead to the formation of fluorene-fused[5]helicene and[4]helicene moiety.Consequently,a total of four stable products were observed.The atomic topographies of products are characterized by bond-resolving scanning tunneling microscopy.The chiral helicity of targeted products can be switched by tip manipulation.Density-functional-theory calculations unveils the reaction pathway of four products.The comparative analysis of their respective energy barriers exhibits a correlation with the experimentally determined yields.Furthermore,we synthesize the polymer chains incorporating non-benzenoid carbohelicenes via the Ullmann reaction of 2,6-dibromo-9,10-di(1-naphthyl)anthracene precursors.Our work proposes a synthetic methodology for several novel helicene-like structures fused with fluorene units and the polymer bearing helicene subunits,thus highlighting the immense potential of these compounds in the application fields of luminescent electronic devices.

关 键 词：HELICENE Scanning tunneling microscopy On-surface synthesis Helicity switching Hydrocarbons Molecular recognition Nanostructures 

分 类 号：O62[理学—有机化学]