Cooperative Ligand Engineering Enabling Stepwise Optimization of Metal-Organic Frameworks for Improved CH Separation from CO and CH.

Acetylene (CH), a critical chemical feedstock, is indispensable in numerous industrial processes. To satisfy the stringent demands for high-purity acetylene, adsorption-based separation techniques have become highly efficient strategies for purifying acetylene from mixtures containing methane and carbon dioxide. In this study, we introduce a novel cooperative ligand engineering strategy that integrates low-symmetry functionalized auxiliary ligands. This innovative approach enables the stepwise synthesis of three zinc-based metal-organic frameworks (MOFs), specifically , , and , which exhibit distinct structural characteristics transitioning from 2D to 3D frameworks. The incorporation of functional groups and framework transformation optimizes the pore environments, thereby creating specific adsorption sites for target gases. Notably, demonstrates superior separation performance, with a CH adsorption capacity of 44.8 cm g at 298 K, and selectivities of 4.28 for CH/CO and 18.6 for CH/CH at 298 K and 1.0 bar. Postsynthetic modification with copper ions further enhances its CH selectivity, achieving values of 6.8 for CH/CO and 20.7 for CH/CH. These results outperform those of many previously reported MOF adsorbents, highlighting the substantial potential of these materials for industrial CH purification.