Tailoring the extrinsic porosity of a vapochromic metal–organic polyhedron for rapid VOC detection

Abstract

Metal-organic polyhedra (MOPs) are intrinsically porous building blocks for the bottom-up construction of hierarchically porous materials. Herein, we report the syntheses of unprecedented solvato- and vapochromic MOP (DGIST-8) nanocrystals and aerogels, each exhibiting a different permanent porosity. Notably, the DGIST-8 aerogels with combined micro-, meso-, and macropores underwent unprecedented color changes perceivable to the naked eye after exposure to volatile organic compounds in both liquid and vapor phases. The key to achieving rapid and reversible vapochromic behavior involves a well-preserved high surface area that ensures the enhanced diffusion of solvent molecules due to the combined presence of micro-, meso- and macropores. The design principles of the vapochromic MOP aerogels disclosed in this report facilitate the use of MOPs as a new type of sensing material.