Robust Supramolecular Nano-Tunnels Built from Molecular Bricks

Chemists are always seeking new methods to construct porous lattice frameworks using simple motifs as the impetus. Different from the extensively reported frameworks which were stabilized by extended bonding, porous crystals of discrete organic molecules is an emerging area of porous materials with dynamic and flexible conformation, consisting exclusively of non-covalent interactions. Herein we report geometrically simple linear molecule that assemble into a supramolecular nano-tunnel through synergy of anionic trident and multiple intermolecular pi-pi stacking interactions. The nano-tunnel crystal exhibit exceptional chemical stability in concentrated HCl and NaOH aqueous solutions, which is rarely been seen in supramolecular organic frameworks and often related to designed extensive hydrogen bonding interactions. Upon thermal treatment, the formed nano-tunnel crystals go through multistage single-crystal-to-single-crystal phase transformations accompanied by thermosalient effect. Aggregation-induced emission joins with the adaptive pores render the crystals with responsive fluorescent change from blue to yellow and visible self-healing porosity transformation upon being stimulated. Furthermore, the desolvated pores exhibit highly selective CO2 adsorption at ambient temperature. <br>