State Key Laboratory of Applied Organic Chemistry (SKLAOC), Key Laboratory of Special Function Materials and Structure Design (MOE), College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , People's Republic of China.
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Energy Materials , Xiamen University , Xiamen 361005 , People's Republic of China.
J Am Chem Soc. 2018 May 30;140(21):6531-6535. doi: 10.1021/jacs.8b02825. Epub 2018 May 2.
Distinguishing structural isomers at the single-molecule level remains a challenge. We report the single-molecule recognition of two diketopyrrolopyrrole containing isomers (SDPP and SPPO) employing the mechanically controllable break junction technique. The single-molecule conductances of the two isomers are indistinguishable under normal conditions. However, reversible protonation and deprotonation of the SPPO in molecular junction result in more than 1 order of magnitude conductance change, which dramatically enhances the conductance difference between the two isomers. Theoretical study reveals that the dramatic conductance switching is due to reversible quantum interference effect. It is suggested that combination of stimuli-response and quantum interference can be an efficient strategy to enhance isomer recognition and conductance switching in single-molecule junctions.
在单分子水平上区分结构异构体仍然是一个挑战。我们报告了使用机械可控的断键技术对两种含有二酮吡咯并吡咯的异构体（SDPP 和 SPPO）进行的单分子识别。在正常条件下，两种异构体的单分子电导率无法区分。然而，分子结中 SPPO 的可逆质子化和去质子化导致电导率变化超过 1 个数量级，这显著增强了两种异构体之间的电导率差异。理论研究表明，这种显著的电导开关是由于可逆量子干涉效应。研究表明，刺激-响应和量子干涉的结合可以成为增强单分子结中异构体识别和电导开关的有效策略。
