The Role of Through-Space Interactions in Modulating Constructive and Destructive Interference Effects in Benzene

Quantum interference effects, whether constructive ordestructive, are key to predicting and understanding the electricalconductance of single molecules. Here, through theory and experiment,we investigate a family of benzene-like molecules that exhibit bothconstructive and destructive interference effects arising due to more thanone contact between the molecule and each electrode. In particular, wedemonstrate that theπ-system of meta-coupled benzene can exhibitconstructive interference and itspara-coupled analog can exhibitdestructive interference, and vice versa, depending on the specificthrough-space interactions. As a peculiarity, this allows a meta-coupled benzene molecule to exhibit higher conductance thana para-coupled benzene. Our results provide design principles for molecular electronic components with high sensitivity tothrough-space interactions and demonstrate that increasing the number of contacts between the molecule and electrodes canboth increase and decrease the conductance