Thienothiophene-centered ladder-type π-systems that feature distinct quinoidal π-extension  

作　　者：Jiaxiang Guo Zeyi Li Tianyu Zhang Xinyu Tian Yue Wang Chuandong Dou 

机构地区：[1]State Key Laboratory of Supramolecular Structure and Materials,College of Chemistry,Jilin University,Changchun 130012,China [2]Jiangsu Engineering Laboratory of Novel Functional Polymeric Materials,Soochow University,Suzhou 215123,China

出　　处：《Chinese Chemical Letters》2024年第5期249-253,共5页中国化学快报（英文版）

基　　金：supported by National Natural Science Foundation of China(Nos.22175074 and 52373182);Jilin Scientific and Technological Development Program(No.20220101054JC).

摘　　要：Quinoidalπ-conjugated structures,a kind of fundamental subunits for organicπ-systems,may produce some intriguing optical,electronic and magnetic properties of polycyclic hydrocarbons(PHs).Herein,we report two thienothiophene-centered ladder-type polycyclic molecules(1 and 2),which possess one quinoidal thienothiophene moiety and two para-quinodimethane(p-QDM)subunits,respectively.As theoretically and experimentally studied,while 1 is a fully closed-shell molecule,2 owns an open-shell structure along with partial contribution of tetraradical state that is induced by the resonance of p-QDM.Moreover,although 2 has a largerπ-conjugated skeleton and open-shell electronic state,it exhibits larger bandgap and blue-shifted absorption.On the other hand,the reversible oxidation activity of 1 enables the preparation of its dication 1^(2+),and the studies on its single-crystal and aromatic structures demonstrate that its two positive charges are delocalized onto the oxygen atoms,thus achieving fullyπ-extended structure and near-infrared absorption.This study not only gains insight into quinoidalπ-subunits,but also provides an important basis for the development of antiaromatic and open-shellπ-electron materials.

关 键 词：Thienothiophene Quinoidal conjugation Open-shell structure AROMATICITY Photophysical properties 

分 类 号：O626[理学—有机化学]