Fine-tuning the pore environment of isoreticular metal-organic frameworks through installing functional sites for boosting C2H6/C2H4 separation

Herein, we presented a strategy that tuning the pore environment via installing functional sites in the pores to boost C2H6/C2H4 separation performance of MOFs. To prove this concept, four isoreticular MOFs [MAF-X10, -X10(Me), -X10(Cl), and -X10(F)] were designed and synthesized based on reticular chemistry principle, which featured the regulated pore environment and exhibited intriguing differences in C2H6 and C2H4 uptakes. Methyl group-modified nonpolar pores endow these MOFs with impressive C2H6-selective behavior and high C2H6 loadings (>110 cm3 g−1), in which MAF-X10(F) with polar F sites exhibited the highest C2H6 uptake (140.5 cm3 g−1) among four MOFs, ranking the top compared to the reported MOF materials. The polar sites-functionalized MAF-X10(Cl) and -X10(F) showed the significantly improved C2H6/C2H4 separation performances in comprehensive of selectivity, separation potential, C2H4 productivity, which were mainly contributed to the strong C-H⋯Cl/F interactions formed between the active sites (Cl or F) in MAF-X10(Cl)/(F) and C2H6, as revealed by molecular simulations.