Department of Physical Chemistry, Institute of Chemistry, University of Graz, Graz, Austria.
Department of Chemistry, University of Liverpool, Liverpool, UK.
Nature. 2023 Sep;621(7977):82-86. doi: 10.1038/s41586-023-06384-y. Epub 2023 Sep 6.
Artificial molecular motors are designed to transform external energy into useful work in the form of unidirectional motion. They have been studied mainly in solution, but also on solid surfaces, which provide fixed reference points, allowing for tracking of their movement. However, these molecules require sophisticated design and synthesis, because the motor function must be imprinted into the chemical structure, and show reduced functionality on surfaces compared with in solution. DNA walkers, on the other hand, impart high directionality as they include the surface as part of the motor function, but they require chemical surface patterning and sequential solvent modification for motor activation. Here we show how efficient motors can operate at much smaller length scales on a homogeneous metal surface without any liquid. This is realized by combining a surface with a simple molecule, which, by itself, does not contain any motor unit. The motion, which is tracked at the single-molecule level, is triggered by intramolecular proton transfer with a corresponding modulation of the potential energy surface. Each molecule moves with 100 percent unidirectionality along an atomically defined straight line. Proof of the motor performing meaningful work is shown by controlled transport of single carbon monoxide molecules. This simplistic concept could form the basis for the controlled bottom-up assembly of nanostructures at the atomic scale.
人工分子马达旨在将外部能量转化为单向运动形式的有用功。它们主要在溶液中进行研究，但也在固体表面进行研究，固体表面提供固定的参考点，允许跟踪它们的运动。然而，这些分子需要复杂的设计和合成，因为马达功能必须被印刻在化学结构中，并且与在溶液中相比，在表面上的功能会降低。另一方面，DNA 行走者赋予了高度的方向性，因为它们将表面作为马达功能的一部分，但它们需要化学表面图案化和顺序溶剂修饰来激活马达。在这里，我们展示了在没有任何液体的情况下，高效的马达如何在更小的金属表面上工作，而无需任何液体。这是通过将一个表面与一个简单的分子结合来实现的，这个分子本身并不包含任何马达单元。通过分子内质子转移来触发运动，同时相应地调节势能表面。每个分子都以 100%的单向性沿着原子定义的直线运动。通过控制单个一氧化碳分子的传输，证明了马达在执行有意义的工作。这个简单的概念可以为原子尺度上的纳米结构的可控自下而上组装提供基础。
