Surface Chemistry Regulation in Cu4I4-Triazolate Metal–Organic Frameworks for One-Step C3H6 Purification from Quaternary C3 Mixtures

C 3 H 6 is a crucial building block for many chemicals, yet separating it from other C 3 hydrocarbons presents a significant challenge. Herein, we report a hydrolytically stable Cu 4 I 4 -triazolate metal–organic framework (MOF) (JNU-9-CH 3 ) featuring 1D channels decorated with readily accessible iodine and nitrogen atoms from Cu 4 I 4 clusters and triazolate linkers, respectively. The exposed iodine and nitrogen atoms allow for cooperative binding of C 3 hydrocarbons, as evidenced by in situ single-crystal crystallography and Raman spectroscopy studies. As a result, JNU-9-CH 3 exhibits substantially stronger binding affinity for C 3 H 4, CH 2 ═C═CH 2, and C 3 H 8 than that for C 3 H 6 . Breakthrough experiments confirm its ability to directly separate C 3 H 6 (≥99.99%) from C 3 H 4 /CH 2 ═C═CH 2 /C 3 H 8 /C 3 H 6 mixtures at varying ratios and flow rates. Overall, we illustrate the cooperative binding of C 3 hydrocarbons in a Cu 4 I 4 -triazolate MOF and its highly efficient C 3 H 6 purification from quaternary C 3 mixtures. The study highlights the potential of MOF adsorbents with metal-iodide clusters for cooperative bindings and hydrocarbon separations.