IBM Research Europe - Zurich, 8803 Rüschlikon, Switzerland.
Applied Physics Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia.
Science. 2022 Jul 15;377(6603):298-301. doi: 10.1126/science.abo6471. Epub 2022 Jul 14.
Controlling selectivity of reactions is an ongoing quest in chemistry. In this work, we demonstrate reversible and selective bond formation and dissociation promoted by tip-induced reduction-oxidation reactions on a surface. Molecular rearrangements leading to different constitutional isomers are selected by the polarity and magnitude of applied voltage pulses from the tip of a combined scanning tunneling and atomic force microscope. Characterization of voltage dependence of the reactions and determination of reaction rates demonstrate selectivity in constitutional isomerization reactions and provide insight into the underlying mechanisms. With support of density functional theory calculations, we find that the energy landscape of the isomers in different charge states is important to rationalize the selectivity. Tip-induced selective single-molecule reactions increase our understanding of redox chemistry and could lead to novel molecular machines.
控制反应的选择性是化学领域的一个持续追求。在这项工作中，我们证明了在表面上通过尖端诱导的氧化还原反应可以实现可逆和选择性的键形成和断裂。通过来自扫描隧道和原子力显微镜组合尖端的施加电压脉冲的极性和幅度，选择导致不同构象异构体的分子重排。反应的电压依赖性的表征和反应速率的确定证明了在构象异构化反应中的选择性，并提供了对潜在机制的深入了解。在密度泛函理论计算的支持下，我们发现不同电荷态下异构体的能量景观对于合理化选择性很重要。尖端诱导的选择性单分子反应增加了我们对氧化还原化学的理解，并可能导致新型分子机器。
