Water-Tolerant Hydrogen-Bonded Organic Framework Based on Phenylbis(benzimidazol-2-yl)methanol: Synthesis, Structural Characterization, and Organic-Vapor-Adsorption Properties

Abstract

Imidazole derivatives are promising building blocks for the construction of hydrogen-bonded organic frameworks (HOFs); however, imidazole-based HOFs are still much less explored than HOFs based on more prominent building blocks, such as carboxy-group-containing organic compounds and 2,4-diaminotriazine moieties. Here, we report a HOF based on phenylbis-(benzimidazol-2-yl)methanol (1). The porous framework of the 1-based HOF is mainly constructed by intermolecular O−H•••N and N−H•••N hydrogen bonds, with ethyl acetate (EtOAc) solvate molecules occupying the pores. The EtOAc guest molecules can be removed by heating (100 °C) the as-synthesized 1-based HOF under reduced pressure or by treating it with supercritical carbon dioxide via a single-crystal-to-single-crystal transformation involving a large framework motion. The desolvated HOF can adsorb the vapors of EtOAc, 2-pentanone, 3pentanone, 2-butanone, diethyl ether, and diethylamine even under high-humidity conditions, which renders the 1-based HOF a promising material for organic-vapor adsorption in the context of industrial applications.