Ultramicroporous Lonsdaleite Topology MOF with High Propane Uptake and Propane/Methane Selectivity for Propane Capture from Simulated Natural Gas.

Propane (CH) is a widely used fuel gas. Metal-organic framework (MOF) physisorbents that are CH selective offer the potential to significantly reduce the energy footprint for capturing CH from natural gas, where CH is typically present as a minor component. Here we report the CH recovery performance of a previously unreported lonsdaleite, , topology MOF, a chiral metal-organic material, [Ni(-IEDC)(bipy)(SCN)], . was prepared from three low-cost precursors: Ni(SCN), -indoline-2-carboxylic acid (-IDECH), and 4,4'-bipyridine (bipy), and its structure was determined by single crystal X-ray crystallography. Pure gas adsorption isotherms revealed that exhibited high CH uptake (2.71 mmol g) at 0.05 bar, an indication of a higher affinity for CH than both CH and CH. Dynamic column breakthrough experiments afforded high purity CH capture from a gas mixture comprising CH/CH/CH (v/v/v = 5/10/85). Despite the dilute CH stream, registered a high dynamic uptake of CH and a breakthrough time difference between CH and CH of 79.5 min g, superior to those of previous MOF physisorbents studied under the same flow rate. Analysis of crystallographic data and Grand Canonical Monte Carlo simulations provides insight into the two CH binding sites in , both of which are driven by C-H···π and hydrogen bonding interactions.