Naghibi Saman, Ismael Ali K, Vezzoli Andrea, Al-Khaykanee Mohsin K, Zheng Xijia, Grace Iain M, Bethell Donald, Higgins Simon J, Lambert Colin J, Nichols Richard J
Department of Chemistry , University of Liverpool , Crown Street , Liverpool L69 7ZD , U.K.
Department of Physics , Lancaster University , Lancaster LA1 4YB , U.K.
J Phys Chem Lett. 2019 Oct 17;10(20):6419-6424. doi: 10.1021/acs.jpclett.9b02319. Epub 2019 Oct 9.
A key area of activity in contemporary molecular electronics is the chemical control of conductance of molecular junctions and devices. Here we study and modify a range of pyrrolodipyridines (carbazole-like) molecular wires. We are able to change the electrical conductance and quantum interference patterns by chemically regulating the bridging nitrogen atom in the tricyclic ring system. A series of eight different N-substituted pyrrolodipyridines has been synthesized and subjected to single-molecule electrical characterization using an STM break junction. Correlations of these experimental data with theoretical calculations underline the importance of the pyrrolic nitrogen in facilitating conductance across the molecular bridge and controlling quantum interference. The large chemical modulation for the -connected series is not apparent for the -series, showing the competition between (i) -connectivity quantum interference phenomena and (ii) the ability of the pyrrolic nitrogen to facilitate conductance, that can be modulated by chemical substitution.
当代分子电子学的一个关键活动领域是分子结和器件电导的化学控制。在这里，我们研究并修饰了一系列吡咯并二吡啶（类咔唑）分子导线。我们能够通过化学调节三环环系中的桥连氮原子来改变电导和量子干涉图案。已经合成了一系列八种不同的N-取代吡咯并二吡啶，并使用STM断结进行单分子电学表征。这些实验数据与理论计算的相关性强调了吡咯氮在促进跨分子桥的电导和控制量子干涉方面的重要性。对于π-连接系列，大的化学调制对于σ-系列并不明显，这表明（i）π-连接量子干涉现象与（ii）吡咯氮促进电导的能力之间的竞争，这种竞争可以通过化学取代来调节。
