Multivariate hydrogen-bonded organic frameworks with tunable permanent porosity for a mustard gas simulant capture.

Abstract

Precise synthesis of topologically predictable and discrete molecular crystals with permanent porosities remains a long-term challenge. Here, we report the first successful synthesis of a series of isoreticular multivariate hydrogen-bonded organic frameworks (MTV-HOFs) from pyrene-based derivatives bearing -H, -CH3, -NH2 and -F groups achieved by a shape-fitted, π-π stacking self-assembly strategy. These MTV-HOFs are single-crystalline materials composed of tectons with as many as 4 different functionalities, verified by single-crystal diffraction, nuclear magnetic resonance (NMR) spectra, and Raman spectra. These MTV-HOFs exhibit tunable hydrophobicity with water uptake starting from 50 to 80% relative humidity, by adjusting the combinations and ratios of functional groups. As a proof of application, the resulting MTV-HOFs were shown to be capable of capturing a mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES) from moisture. The location of different functional groups within the pores of MTV-HOFs leads to a synergistic effect, which resulted in a superior CEES/H2O selectivity (up to 94%) to that of the HOFs with only pure component and enhanced breakthrough performance (up to 4000 min/g) when compared to benchmark MOF materials. The synthesis of MTV-HOFs provides a platform for the development of porous molecular materials for numerous applications.