l ‐Leucine‐Based Layered Coordination Polymer Supports for Immobilizing Basic Salts to Yield Solid CO ₂ Adsorbents Resistant to Moisture and Oxidation

We demonstrate that amino acid‐based coordination polymers can serve as supports for a variety of basic salts. A layered framework, bis( l ‐leucinato)zinc(II), Zn(Leu) 2 , prepared by an aqueous, base‐mediated procedure, provides crystallographically defined, carboxylato‐bridged two‐dimensional layered structures with intersheet surfaces. The interlayer spacing is molecularly tunable, and immobilizing potassium l ‐leucinate increases the interlayer spacing in two discrete steps. Using this host, diverse basic salts can be immobilized to give solid sorbents that remain macroscopic solids under humid, DAC‐relevant conditions (400 ppm CO 2 , 293 K dew point, 313 K) while delivering equilibrium CO 2 uptakes of 0.17–1.04 mmol g −1 . After accelerated oxidative aging in simulated air (400 ppm CO 2 , 21% O 2 , 293 K dew point) at 393 K for 24 h, the amino acid‐based sorbent shows high retention in CO 2 capacity, whereas a conventional polyamine‐based sorbent exhibits a marked decrease in the capacity. The combination of environmental durability and DAC‐relevant performance establishes Zn(Leu) 2 as a general and modular platform for sustainable CO 2 capture technologies.