Shape-persistent pyrrole-based covalent organic cages: synthesis, structure and selective gas adsorption properties.

Two cryptand-like, shape persistent [2+3] imine cages (1 and 2) derived from oligopyrrolic precursors (diformyl dipyrrylpyridine 3 and diformyl bipyrrole 4) were prepared. These cages contain open cavities as inferred from solid state structural analyses and act as selective CO2 gas adsorbing materials in the solid state.