Decoding and Exploiting Kinetic Pathways in Dynamic Covalent Cage Formation via Isolated Macrocycle Precursors

Synthesis of porous organic cages by dynamic covalent chemistry usually results in structures with high symmetry. Reduced-symmetry cages are currently much harder to access selectively due to component self-sorting controlled by thermodynamics. Here, we show that formation of kinetically-trapped [2+3] rylene diimide cages can be intercepted permitting isolation and full characterization of lower-order [2+2] macrocyclic intermediates by 1D and 2D NMR spectroscopies, high-resolution mass spectrometry, and single crystal X-ray diffraction analysis. We investigate their kinetic behaviour and subsequently demonstrate that these shallow kinetic traps may act as effective precursors for selective synthesis of organic cages, including a multicomponent cage with a reduced symmetry. This work highlights the critical role of intermediates that govern the formation of kinetically-trapped porous organic cages and introduces a hitherto unexplored strategy to accomplish synthesis of organic cages with reduced symmetry incorporating multiple functionalities.