Copper-related materials are used for separation of ethylene and acetylene gases in chemistry; however, the precise mechanism regarding selectivity is elusive to be fully understood. Here, we have conducted a joint experimental and theoretical study of the Cun- (n = 7-30) clusters in reacting with C2H4 and C2H2. It is found that all of the Cun- clusters readily react with C2H2, giving rise to C2H2-addition products; however, Cu18- and Cu19- do not react with C2H4. We illustrate the superatomic stability of Cu18- and advocate its availability to separate C2H4 from C2H2. Further, we demonstrate the atomically precise mechanism regarding selectivity by fully unveiling the size-dependent cluster-π interactions.

中文翻译：

---

探测 Cun- 和 C2H2/C2H4 之间的簇-π 相互作用以进行气体分离。

与铜有关的材料在化学上用于分离乙烯和乙炔气体；然而，关于选择性的精确机制难以完全理解。在这里，我们对 Cun- (n = 7-30) 簇与 C2H4 和 C2H2 反应进行了联合实验和理论研究。发现所有的 Cun-cun-cluster 很容易与 C2H2 反应，产生 C2H2-加成产物；但是，Cu18- 和 Cu19- 不与 C2H4 反应。我们说明了 Cu18- 的超原子稳定性，并主张其可用于将 C2H4 与 C2H2 分离。此外，我们通过完全揭示与尺寸相关的簇-π 相互作用来展示关于选择性的原子精确机制。