Wang Rui, Song Kai, Wei Caiyun, Hong Wenjing, Zang Yaping, Qu Dahui, Li Hongxiang
Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China.
Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing, 100190, P. R. China.
Phys Chem Chem Phys. 2022 Jan 26;24(4):2227-2233. doi: 10.1039/d1cp04671c.
The understanding of charge transport at a single molecule level is a prerequisite for the fabrication of molecular devices. Here, the relationship between molecular conductance, substitution pattern and stimuli response in BN-embedded aromatics was systematically investigated using the break junction technique. It was found that the -phenylthioether-anchored BN molecule (-BN-) shows the highest conductance of 10, and the -phenylthioether-anchored BN molecule (-BN-) exhibits the lowest conductance which is lower than the instrument detection limit (<10). The -BN- and -BN- molecules, with both - and -substituted anchor groups on two termini, show moderate conductances of 10 and 10, respectively. The conductance difference is interpreted as a distinct quantum interference effect caused by the substitution pattern of the anchoring groups. Notably, their conductance changes slightly upon coordination with a fluoride ion, in spite of the distinct change of their frontier orbital energy levels. These results demonstrate that, in addition to the frontier orbital energy levels, the anchors play an important role in the design of stimuli-responsive molecular electronic devices with a high on/off current ratio.
在单分子水平上理解电荷传输是制造分子器件的前提条件。在此，利用断结技术系统地研究了嵌入硼氮（BN）的芳烃中分子电导、取代模式与刺激响应之间的关系。研究发现，以苯硫醚为锚定基团的硼氮分子（-BN-）显示出最高电导为10，而以苯硫醚为锚定基团的硼氮分子（-BN-）表现出最低电导，低于仪器检测限（<10）。在两个末端均带有-和-取代锚定基团的-BN-和-BN-分子分别显示出中等电导，为10和10。电导差异被解释为由锚定基团的取代模式引起的明显量子干涉效应。值得注意的是，尽管其前沿轨道能级发生了明显变化，但它们与氟离子配位后电导变化很小。这些结果表明，除了前沿轨道能级外，锚定基团在设计具有高开/关电流比的刺激响应分子电子器件中起着重要作用。
