Department of Physics, Lancaster University, Lancaster LA1 4YB, UK.
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland.
Nat Commun. 2015 Mar 3;6:6389. doi: 10.1038/ncomms7389.
A quantum circuit rule for combining quantum interference effects in the conductive properties of oligo(phenyleneethynylene) (OPE)-type molecules possessing three aromatic rings was investigated both experimentally and theoretically. Molecules were of the type X-Y-X, where X represents pyridyl anchors with para (p), meta (m) or ortho (o) connectivities and Y represents a phenyl ring with p and m connectivities. The conductances GXmX (GXpX) of molecules of the form X-m-X (X-p-X), with meta (para) connections in the central ring, were predominantly lower (higher), irrespective of the meta, para or ortho nature of the anchor groups X, demonstrating that conductance is dominated by the nature of quantum interference in the central ring Y. The single-molecule conductances were found to satisfy the quantum circuit rule Gppp/Gpmp=Gmpm/Gmmm. This demonstrates that the contribution to the conductance from the central ring is independent of the para versus meta nature of the anchor groups.
我们研究了具有三个芳环的寡聚（苯乙炔）（OPE）型分子的导电性质中量子干涉效应的组合的量子电路规则，从实验和理论两方面进行了研究。分子为 X-Y-X 型，其中 X 代表带有对位（p）、间位（m）或邻位（o）连接的吡啶锚，而 Y 代表带有 p 和 m 连接的苯基环。具有中央环中 m 连接（p 连接）的 X-m-X（X-p-X）形式的分子的电导 GXmX（GXpX）主要较低（较高），与锚定基团 X 的间位、对位或邻位性质无关，表明电导主要由中央环 Y 中的量子干涉性质决定。单分子电导满足量子电路规则 Gppp/Gpmp=Gmpm/Gmmm。这表明来自中央环的贡献与锚定基团的对位与间位性质无关。
