Amino-Functionalized Metal–Organic Frameworks Featuring Ultra-Strong Ethane Nano-Traps for Efficient C₂H₆/C₂H₄ Separation

Developing high-performance porous materials to separate ethane from ethylene is an important but challenging task in the chemical industry, given their similar sizes and physicochemical properties. Herein, a new type of ultra-strong C₂H₆ nano-trap, CuIn(3-ain)₄ is presented, which utilizes multiple guest-host interactions to efficiently capture C₂H₆ molecules and separate mixtures of C₂H₆ and C₂H₄. The ultra-strong C₂H₆ nano-trap exhibits the high C₂H₆ (2.38 mmol g⁻¹) uptake at 6.25 kPa and 298 K and demonstrates a remarkable selectivity of 3.42 for C₂H₆/C₂H₄ (10:90). Additionally, equimolar C₂H₆/C₂H₄ exhibited a superior high separation potential ∆Q (2286 mmol L⁻¹) at 298 K. Kinetic adsorption tests demonstrated that CuIn(3-ain)₄ has a high adsorption rate for C₂H₆, establishing it as a new benchmark material for the capture of C₂H₆ and the separation of C₂H₆/C₂H₄. Notably, this exceptional performance is maintained even at a higher temperature of 333 K, a phenomenon not observed before. Theoretical simulations and single-crystal X-ray diffraction provide critical insights into how selective adsorption properties can be tuned by manipulating pore dimensions and geometry. The excellent separation performance of CuIn(3-ain)₄ has been confirmed through breakthrough experiments for C₂H₆/C₂H₄ gas mixtures.