Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, PR China.
School of physics, University of Chinese Academy of Sciences, Beijing, 100049, PR China.
Nat Commun. 2023 Apr 13;14(1):2100. doi: 10.1038/s41467-023-37904-z.
The origin of homochirality in nature is an important but open question. Here, we demonstrate a simple organizational chiral system constructed by achiral carbon monoxide (CO) molecules adsorbed on an achiral Au(111) substrate. Combining scanning tunneling microscope (STM) measurements with density-functional-theory (DFT) calculations, two dissymmetric cluster phases consisting of chiral CO heptamers are revealed. By applied high bias voltage, the stable racemic cluster phase can be transformed into a metastable uniform phase consisting of CO monomers. Further, during the recondensation of a cluster phase after lowering down bias voltage, an enantiomeric excess and its chiral amplification occur, resulting in a homochirality. Such asymmetry amplification is found to be both kinetically feasible and thermodynamically favorable. Our observations provide insight into the physicochemical origin of homochirality through surface adsorption and suggest a general phenomenon that can influence enantioselective chemical processes such as chiral separations and heterogeneous asymmetric catalysis.
自然界中手性的起源是一个重要但尚未解决的问题。在这里，我们展示了一种由非手性一氧化碳 (CO) 分子在非手性 Au(111) 衬底上吸附而构建的简单组织手性体系。通过扫描隧道显微镜 (STM) 测量和密度泛函理论 (DFT) 计算相结合，揭示了由手性 CO 七聚体组成的两个不对称团簇相。通过施加高偏置电压，可以将稳定的外消旋团簇相转变为由 CO 单体组成的亚稳均匀相。此外，在降低偏置电压后团簇相重新冷凝时，会发生对映体过量和手性放大，从而产生手性。这种不对称放大在动力学上是可行的，在热力学上也是有利的。我们的观察结果通过表面吸附为手性起源提供了深入的物理化学见解，并表明了一种普遍现象，这种现象可能会影响手性分离和多相不对称催化等手性选择性化学反应过程。
