School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K.
J Am Chem Soc. 2021 Mar 17;143(10):3817-3829. doi: 10.1021/jacs.0c11605. Epub 2021 Feb 19.
The most probable single-molecule conductance of each member of a series of 12 conjugated molecular wires, 6 of which contain either a ruthenium or platinum center centrally placed within the backbone, has been determined. The measurement of a small, positive Seebeck coefficient has established that transmission through these molecules takes place by tunneling through the tail of the HOMO resonance near the middle of the HOMO-LUMO gap in each case. Despite the general similarities in the molecular lengths and frontier-orbital compositions, experimental and computationally determined trends in molecular conductance values across this series cannot be satisfactorily explained in terms of commonly discussed "single-parameter" models of junction conductance. Rather, the trends in molecular conductance are better rationalized from consideration of the complete molecular junction, with conductance values well described by transport calculations carried out at the DFT level of theory, on the basis of the Landauer-Büttiker model.
已经确定了一系列 12 个共轭分子线中每个成员的最可能的单分子电导率，其中 6 个分子线在骨架的中心位置分别包含钌或铂中心。通过测量小的正塞贝克系数已经确定，这些分子的传输是通过在每种情况下 HOMO-LUMO 间隙中间的 HOMO 共振的尾部进行隧道传输来实现的。尽管分子长度和前沿轨道组成通常具有相似性，但在整个系列中，实验和计算确定的分子电导率值趋势不能用通常讨论的结电导率的“单参数”模型来令人满意地解释。相反，从完整分子结的角度考虑，分子电导率的趋势可以更好地合理化，基于基于 Landauer-Büttiker 模型的 DFT 理论水平进行的传输计算可以很好地描述电导率值。
