An adenine-based metal-organic framework with tailored pore environment for adsorption separation of C2H2 from C2H4 and CO2

The separation of ethyne (C2H2) from mixtures with ethylene (C2H4) and carbon dioxide (CO2) is crucial yet challenging in the chemical industry. Based on the adsorption separation technology, it is desirable to design and develop efficient adsorbents for C2H2 separation. In this work, we present an adenine-based metal-organic framework (Cu-AD-HEA), which features tailored pore environment with Lewis basic sites within the specific intersecting channels for the separation of C2H2 from mixtures with C2H4 and CO2. The obtained Cu-AD-HEA exhibits exceptional adsorption capacity for C2H2 and demonstrates competitive adsorption selectivity for C2H2/C2H4 and C2H2/CO2. Furthermore, dynamic breakthrough results further illustrate the superior dynamic separation of C2H2 over C2H4 and CO2. Moreover, detailed molecular simulations and density functional theory (DFT) calculations elucidate that C2H2 is preferentially captured in a tailored pore environment of Cu-AD-HEA with stronger binding affinity through CH⋯N/O hydrogen bonds and C–H⋯π or π⋯π interactions. This work offers an effective MOF-based adsorbent for the separation of C2H2 from mixtures with C2H4 and CO2.