Surface Chemistry Regulation\nin Cu<sub>4</sub>I<sub>4</sub>‑Triazolate Metal–Organic\nFrameworks for One-Step\nC<sub>3</sub>H<sub>6</sub> Purification from Quaternary C<sub>3</sub> Mixtures

C<sub>3</sub>H<sub>6</sub> is a crucial building block\nfor many\nchemicals, yet separating it from other C<sub>3</sub> hydrocarbons\npresents a significant challenge. Herein, we report a hydrolytically\nstable Cu<sub>4</sub>I<sub>4</sub>-triazolate metal–organic\nframework (MOF) (JNU-9-CH<sub>3</sub>) featuring 1D channels decorated\nwith readily accessible iodine and nitrogen atoms from Cu<sub>4</sub>I<sub>4</sub> clusters and triazolate linkers, respectively. The\nexposed iodine and nitrogen atoms allow for cooperative binding of\nC<sub>3</sub> hydrocarbons, as evidenced by <i>in situ</i> single-crystal crystallography and Raman spectroscopy studies. As\na result, JNU-9-CH<sub>3</sub> exhibits substantially stronger binding\naffinity for C<sub>3</sub>H<sub>4</sub>, CH<sub>2</sub>CCH<sub>2</sub>, and C<sub>3</sub>H<sub>8</sub> than that for C<sub>3</sub>H<sub>6</sub>. Breakthrough experiments confirm its ability to directly\nseparate C<sub>3</sub>H<sub>6</sub> (≥99.99%) from C<sub>3</sub>H<sub>4</sub>/CH<sub>2</sub>CCH<sub>2</sub>/C<sub>3</sub>H<sub>8</sub>/C<sub>3</sub>H<sub>6</sub> mixtures at varying\nratios and flow rates. Overall, we illustrate the cooperative binding\nof C<sub>3</sub> hydrocarbons in a Cu<sub>4</sub>I<sub>4</sub>-triazolate\nMOF and its highly efficient C<sub>3</sub>H<sub>6</sub> purification\nfrom quaternary C<sub>3</sub> mixtures. The study highlights the potential\nof MOF adsorbents with metal-iodide clusters for cooperative bindings\nand hydrocarbon separations.