Chemical Research in Chinese Universities ›› 2023, Vol. 39 ›› Issue (2): 224-227.doi: 10.1007/s40242-022-2136-4

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Removing the Destructive Quantum Interference in Cross Conjugation System by Structural Restraint

QU Kai2,4,6, PAN Zi-You1,2, WANG Jin-Yun2, ZHANG Bochao3, ZENG Hao2, SANG Yu-Feng2,4, ZHANG Qian-Chong2,5, CHEN Zhong-Ning2,5   

  1. 1. College of Chemistry, Fuzhou University, Fuzhou 350108, P. R. China;
    2. State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, P. R. China;
    3. Department of Pharmacy, Xiamen Medical College, Xiamen 361005, P. R. China;
    4. School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, P. R. China;
    5. Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou 350108, P. R. China;
    6. University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2022-04-11 Online:2023-04-01 Published:2023-03-16
  • Contact: ZHANG Qian-Chong E-mail:zhangqianchong@fjirsm.ac.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (No.92061117), the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000), the Project of the Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZR129) and the Natural Science Foundation of Fujian Province, China(No.2020J01110).

Abstract: Understanding the quantum effect in the cross-conjugated system is of fundamental significance in molecular electronics. In this study, four molecules Xa-O, Xa, BP and BP-O were synthesized to investigate the destructive quantum interference(DQI) of a carbonyl bridge. The single-molecule conductance measured by the scanning tunneling microscope break junction(STM-BJ) technique demonstrates an increase in the conductance from molecule BP-O to molecule Xa-O as the cross-conjugated system is extended. Theoretical calculations show that the explicit DQI feature is presented in BP-O but absent in Xa-O, which indicates the removal of DQI in the restrained structures and results in the conductance enhancement in Xa-O.

Key words: Single-molecule conductance, Cross conjugation, Quantum interference, Carbonyl, Conductance enhancement