Self-adaptive Coordination Evolution Mediated Pore-Space-Partition in Metal-Organic Frameworks for Boosting SF6/N2 Separation

Abstract

The controllable and precise structural regulation of metal-organic frameworks (MOFs) based on isoreticular chemistry is an effective strategy for creating functional material platforms, such as efficient porous adsorbents. Herein, for the first time, mediated by an unprecedented self-adaptive coordination evolution (SACE) on pseudo-D2h-symmetric [M4(μ3-O)2(COO)6] (M = Mn/Fe) clusters, two pore space partitioned MOFs (CTGU-47-Mn/Fe, CTGU = China Three Gorges University) have been successfully constructed. Owing to the more confined adsorption space and dense binding sites produced by pore space partitioning (PSP), the CTGU-47-Mn/Fe exhibit significantly enhanced performance in the capture or recovery SF6 (greenhouse/electronic specialty gas) from SF6/N2 mixture compared to their non-partitioned homologous structures (CTGU-46-Mn/Fe) with adsorption selectivity increased from 37/72 to 634/157 (v/v, 10/90, 100 kPa). The theoretical calculations also elucidated that the implementation of PSP within CTGU-47-Mn/Fe leads to dramatically strengthened binding affinity for SF6 over N2 through extra multiple F···H interactions. This study represents a valuable advance in crystal engineering field: the SACE of polynuclear metal clusters is expected to be useful in the structural regulation of MOFs and the fabrication of advanced porous adsorbents.