Amide-functionalized metal–organic frameworks: Syntheses, structures and improved gas storage and separation properties

Abstract

Metal–organic frameworks (MOFs), emerging as a new type of solid state porous material, have received intensive attention in academia and industry over the last two decades. MOF materials demonstrate not only intriguing structures/topologies, but also a variety of functionalities/applications, i.e., mediating the currentdemanding energy crisis and environmental pollution. We are interested in the design and self-assembly of functional MOF materials to improve carbon dioxide, hydrogen, methane and acetylene storage capabilities, as well as the separation efficiencies toward flue gas and nature gas. Therefore, significant efforts have been devoted to construct a subclass of amide-functionalized metal–organic frameworks (AFMOFs) in the last decade in our research group to target the above-mentioned applications. Due to the intrinsic nature, i.e., flexibility and polarizability of amide groups, the resultant AFMOFs unveil a myriad of graceful structures/topologies in combination with enhanced gas storage and separation properties. Depending on where the amide groups are implanted into the organic backbones, two types of AFMOFs were essentially afforded in our research group. In this review, we first pay some attention to the synthesis and structures of dynamic AFMOFs, in which the amide groups are built between carboxymethyl and phenyl rings, then we discuss the designs, syntheses and constructions of robust AFMOFs by means of several intriguingly topological platforms, i.e., pcu-, agw-, nbo-, rht-, pbz- and txt-MOFs, where the amide groups are built between two phenyl rings. Later, several outstanding AFMOFs are chosen to elucidate their applications for energy gas storage and carbon capture, as well as acetylene safe handling.