Anion Regulates scu Topological Porous Coordination Polymers into the Acetylene Trap.

The development of efficient porous absorbents with high uptake and selectivity remains a great challenge, especially for the recovery of acetylene (C 2 H 2 ) from its carbon dioxide (CO 2 )-containing mixtures. Here, we propose and report an anion-planting strategy for regulating the scu topological porous coordination polymers (PCPs) into the C 2 H 2 trap. The three electronegative anions SiF 6 2- , TiF 6 2- , and ZrF 6 2- , in addition to the ligand of 3,5-di(1H-imidazol-1-yl)benzoic acid ( HL ) and Cu 2+ ion, were employed to construct highly porous PCPs ( NTU-60 , NTU-61 , and NTU-62 ) with varied window aperture. Especially, due to a matching distance ( d F-F ) of 5.7 Å along the c -axis, the limited space that can be assigned as a single C 2 H 2 trap enables NTU-61 to show optimal ability for C 2 H 2 (van der Waals (vdW) parameters of the two H atoms: ∼5.72 Å) recognition, validated by Grand Canonical Monte Carlo (GCMC) calculations and Raman spectra. These characteristics allow the NTU-series to show higher C 2 H 2 uptake, as well as excellent C 2 H 2 /CO 2 separation performance under dynamic conditions. The molecular insight and strategy here not only permit balanced adsorption and separation in a single domain but also exhibit an opportunity to develop advanced adsorbents in nearly all frameworks with lattice or coordinated ions, which may act as the platforms for various selective guest trappings with on-demand time and/or spatial resolution.