Concomitant Covalent and Noncovalent Assembly: Self-Assembly of Sublimable Caffeine in the Formation of Microporous Organic Polymer for Morphology Evolution and Enhanced Performance

This work introduces a so-called "caffeine method"for morphology evolution of microporous organic polymer (MOP). In a proper reaction medium such as triethylamine, caffeine undergoes dynamic self-assembly to 1D crystalline morphologies. The resultant caffeine powder is sublimable. The Sonogashira coupling of multiethynylarenes with multihaloarenes was conducted with the concomitant self-assembly of caffeine in triethylamine to form MOP materials. Through the removal of caffeine from the MOP materials via sublimation, the morphologies of MOP were engineered to 1D ribbon-like or tubular materials. The caffeine method could be applied to shape-controlled synthesis of emissive and catalytic MOP materials. Compared to conventional irregular MOP powder prepared without caffeine, the 1D morphological MOP materials showed enhanced sensing and catalytic performance, due to the thin thicknesses and reduced diffusion pathways of the substrates.