Synthesis and applications of porous organic cages

Abstract

Solids composed of shape-persistent organic cage molecules are an emerging class of porous materials. Research in this area has recently progressed from understanding the nature of porosity in these materials to finding applications suited to their unique properties. For example, given that the cages are held together in the solid state by relatively weak (compared to covalent interactions) dispersion forces, the resultant materials are structurally flexible and thus physical properties, such as porosity, that can be modulated according to the adsorbate to which it is exposed. Moreover, discrete cages are soluble and can thus be reprecipitated as structural polymorphs that possess different properties, or processed into thin layers or composite materials such as mixed matrix membranes. In this review, we highlight the synthetic strategies that have been employed to produce porous organic cages and discuss recent advances in design concepts that have led to ultraporous solids. We will also canvass recent applications of these materials and posit potential areas of development.