Device Modelling Group, School of Engineering, University of Warwick, Coventry, CV4 7AL, UK.
Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.
Angew Chem Int Ed Engl. 2023 Jun 12;62(24):e202302150. doi: 10.1002/anie.202302150. Epub 2023 May 4.
Most studies in molecular electronics focus on altering the molecular wire backbone to tune the electrical properties of the whole junction. However, it is often overlooked that the chemical structure of the groups anchoring the molecule to the metallic electrodes influences the electronic structure of the whole system and, therefore, its conductance. We synthesised electron-accepting dithienophosphole oxide derivatives and fabricated their single-molecule junctions. We found that the anchor group has a dramatic effect on charge-transport efficiency: in our case, electron-deficient 4-pyridyl contacts suppress conductance, while electron-rich 4-thioanisole termini promote efficient transport. Our calculations show that this is due to minute changes in charge distribution, probed at the electrode interface. Our findings provide a framework for efficient molecular junction design, especially valuable for compounds with strong electron withdrawing/donating backbones.
大多数分子电子学的研究都集中在改变分子键的骨架上，以调整整个结的电性能。然而，人们常常忽略了将分子固定在金属电极上的基团的化学结构会影响整个系统的电子结构，从而影响其电导。我们合成了受电子的二噻吩并磷氧化物衍生物，并制备了它们的单分子结。我们发现，锚定基团对电荷输运效率有显著的影响：在我们的例子中，缺电子的 4-吡啶基团会抑制电导，而富电子的 4-硫代茴香醚末端则会促进有效的输运。我们的计算表明，这是由于在电极界面处探测到的电荷分布的微小变化所致。我们的研究结果为高效的分子结设计提供了一个框架，特别是对于具有强吸电子/供电子骨架的化合物，这是非常有价值的。
