Angew. Chem. Int. Ed.: Spiro-Conjugated π–σ–π Architectures Enable Single-Molecule Insulators via Destructive Quantum Interference

Authors：

Zhe-Hong Yu^1#, Chengjia Jing^2,3#, Yang-Kun Qu¹, Mingliang Zhang^2,3, Shi-Jie Ge¹, Cheng Zhong⁴, Rui-Hong Liu¹, Yaping Zang^2,3*, and Zuo-Quan Jiang¹*

Institution：

¹State Key Laboratory of Bioinspired Interfacial Materials Science,Institute of Functional Nano & Soft Materials (FUNSOM), SoochowUniversity, Suzhou, Jiangsu 215123, P.R. China

²Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China

³University of Chinese Academy of Sciences, Beijing 100049, P.R.China

⁴Hubei Key Lab on Organic and Polymeric Optoelectronic Materials,Department of Chemistry and Molecular Science, Wuhan University,Wuhan 430072, P.R. China

Abstract：

Controlling molecular conductance beyond highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO–LUMO) interference is essential for advancing single-molecule electronics. Here we employ π–σ–π frameworks—linear diphenylmethane and orthogonal 9,9′-spirobifluorene—to investigate destructive quantum interference (DQI) governed by orbitals on the same side. Four model molecules (DM22-MT, DM44-MT, SF33-MT, SF44-MT) were designed with site-specific –SMe anchoring groups and examined by scanning tunneling microscope–break junction (STM–BJ) measurements and theoretical simulations. All exhibit intrinsically low conductance, consistent with destructive quantum interference (DQI) effect. Importantly, site-dependent effects in spiro systems disrupt spiro-conjugation and alter anchor–electrode coupling, leading to counterintuitive conductance trends. This study provides the first experimental evidence for bilateral DQI in π–σ–π systems and establishes a molecular design strategy for insulating and functionalized single-molecule devices.

IF：

16.9

Link：

https://doi.org/10.1002/anie.202523778