Synergistic binding sites in a hybrid ultramicroporous material for one-step ethylene purification from ternary C hydrocarbon mixtures.

One-step separation of CH from ternary CH/CH/CH hydrocarbon mixtures is of great significance in the industry but is challenging due to the similar sizes and physical properties of CH, CH, and CH. Here, we report an anion-pillared hybrid ultramicroporous material, CuTiF-TPPY, that has the ability of selective recognition of CH over CH and CH. The 4,6-connected framework of CuTiF-TPPY exhibits semi-cage-like one-dimensional channels sustained by porphyrin rings and TiF pillars, which demonstrates the noticeably enhanced adsorption of CH and CH over CH. Dynamic breakthrough experiments confirm the direct and facile high-purity CH (>99.9%) production from a ternary gas mixture of CH/CH/CH (1/9/90, v/v/v) under ambient conditions. Computational studies and in situ infrared reveal that the porphyrin moieties with large π-surfaces form multiple van der Waals interactions with CH; meanwhile, the polar TiF pillars form C-H•••F hydrogen bonding with CH. In contrast, the recognition sites for CH in the framework are less marked.