Constructive Quantum Interference in Single‐Molecule Benzodichalcogenophene Junctions

• Published in: Chemistry : a European journal Vol. 26; no. 23; pp. 5264 - 5269
• Main Authors: Baghernejad, Masoud, Yang, Yang, Al‐Owaedi, Oday A., Aeschi, Yves, Zeng, Biao‐Feng, Abd Dawood, Zahra Murtada, Li, Xiaohui, Liu, Junyang, Shi, Jia, Decurtins, Silvio, Liu, Shi‐Xia, Hong, Wenjing, Lambert, Colin J.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 21.04.2020
• Subjects: Aromatic compounds; Aromatic hydrocarbons; Chemistry; Conductance; Cores; density functional calculations; Electrical junctions; Hydrocarbons; Interference; perturbation theory; quantum interference; Resistance; scanning tunneling microscopy; single-molecule conductors; Substitutes; density functional calculations; perturbation theory; quantum interference; scanning tunneling microscopy; single-molecule conductors
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201905878

Heteroatom substitution into the cores of alternant, aromatic hydrocarbons containing only even‐membered rings is attracting increasing interest as a method of tuning their electrical conductance. Here, the effect of heteroatom substitution into molecular cores of non‐alternant hydrocarbons, containing odd‐membered rings, is examined. Benzodichalcogenophene (BDC) compounds are rigid, planar π‐conjugated structures, with molecular cores containing five‐membered rings fused to a six‐membered aryl ring. To probe the sensitivity or resilience of constructive quantum interference (CQI) in these non‐bipartite molecular cores, two C2‐symmetric molecules (I and II) and one asymmetric molecule (III) were investigated. I (II) contains S (O) heteroatoms in each of the five‐membered rings, while III contains an S in one five‐membered ring and an O in the other. Differences in their conductances arise primarily from the longer S−C and shorter O−C bond lengths compared with the C−C bond and the associated changes in their resonance integrals. Although the conductance of III is significantly lower than the conductances of the others, CQI was found to be resilient and persist in all molecules. Heteroatom substitution into the cores of alternant, aromatic hydrocarbons containing only even‐membered rings is attracting increasing interest as a method of tuning their electrical conductance. Here, the effect of heteroatom substitution into molecular cores of non‐alternant hydrocarbons, containing odd‐membered rings, is examined.