A Cluster‐to‐Cluster Direct‐Linked Al 8 ‐Cd Heterometallic MOF: Construction and Efficient C 3 H 6 /C 2 H 4 Separation Performance

ABSTRACT The separation of light olefins is a crucial process in the petrochemical industry, and developing advanced adsorbent materials is very significant. Aluminum (Al) cluster‐based heterometallic frameworks possess great application prospects but have rarely been investigated for separation applications. Herein, we propose a novel cluster‐to‐cluster direct‐linking strategy, abandoning the conventional organic linker bridging approach, and a new Al cluster‐based Al 8 Cd heterometallic MOF (Al 8 ‐CdCl 2 ‐1) was constructed. The MOF contains interesting saddle‐shaped Al 8 clusters, which are directly bonded to Cd 2 Cl 2 clusters, forming an uncommon 4,8‐connected 3D heterometallic framework with flu topology, and possessing a solvent‐accessible porosity of 41.7% with channels decorated by Cl − anionic sites. The activated materials with good stability exhibit pronounced adsorption selectivity of 4.2‒4.4 for C 3 H 6 over C 2 H 4 . Dynamic breakthrough experiments demonstrate the direct production of high‐purity C 2 H 4 (≥ 99.9%) and C 3 H 6 (≥ 99.5%) in a single step. Theoretical calculations provide in‐depth insight into the adsorption mechanism, revealing that C 3 H 6 molecules interact with the pore walls through stronger multiple interactions compared with C 2 H 4 , accounting for the preferential adsorption. This direct intercluster linkage removes fragile organic bridging moieties and markedly improves the robustness of the framework. Meanwhile, abundant exposed chloride adsorption sites are precisely embedded within channels, which boosts olefin separation performance.