Quadruple[6]Helicene Featuring Pyrene Core:Unraveling Contorted Aromatic Core with Larger Effective Conjugation  

作　　者：Christopher Wallerius Otgonbayar Erdene-Ochir Eva Van Doeselar Ronald Alle Anh Tu Nguyen Marvin F.Schumacher Arne Lützen Klaus Meerholz Sai Ho Pun 

机构地区：[1]Department of Chemistry,University of Cologne,Cologne 50939,Germany [2]Kekulé-Institute of Organic Chemistry and Biochemistry,University of Bonn,Bonn 53121,Germany [3]Department of Chemistry,Hong Kong University of Science and Technology,Clean Water Bay,Hong Kong,China

出　　处：《Precision Chemistry》2024年第9期488-494,共7页精准化学（英文）

基　　金：supported by Deutsche Forschungsgemeinschaft(DFG)through RTG 2591“Template-Designed Organic Electronics”;the Manchot Foundation for a doctoral scholarship.

摘　　要：Multiple helicenes display distinct aromatic cores characterized by highly twisted rings that are shared or fused with constituent helicene moieties.Diversifying these aromatic cores unlocks avenues for creating multiple helicenes with distinct properties and topologies.Herein we report the synthesis of a quadruple[6]helicene featuring pyrene as the aromatic core.The synthesis involved key steps of the annulativeπ-extension reaction and Scholl reaction.By extending multiple helicenes along the axial direction,the degree of contortion of the aromatic core can be controlled from nearly flat to highly twisted.Notably,quadruple[6]-helicene exhibits a significant red-shift of 0.49 eV compared to quadruple[4]-helicenes,of which the red-shift arises from bothπ-extension and augmented effective conjugation due to enhanced twisting.Quantum chemical calculations demonstrate that the degree of contortion in the pyrene core adeptly governs the energy levels of the HOMO and LUMO,which offers an alternative strategy beyond mere enlargement of theπbackbone.An intriguing serendipitous finding reveals the formation of one-molecule-thick supramolecular homochiral nanosheets through selfinterlocking interactions of enantiomers in single crystals,a rare packing motif for multiple helicenes.

关 键 词：HELICENES Polycyclic aromatics PYRENE Core contortion Effective conjugation 

分 类 号：O62[理学—有机化学]