Construction of Nanoscale Covalent Organic Frameworks via Photocatalysis-Involved Cascade Reactions for Tumor-Selective Treatment

Photocatalysis is a powerful tool in modern organic synthesis, however, it has not been applied to the synthesis of covalent organic frameworks (COFs), even in synthetic cascade approaches. Herein, the construction of a series of imine-linked COFs from benzyl ethers and aromatic amines via sequential visible-light-induced photocatalytic oxidation and imine condensation steps is reported. The synthesis is performed under ambient conditions and is readily expanded to the gram-scale. This strategy results in imine-linked COFs possessing a uniform particle size with regular spherical morphology which may be particularly suitable for biomedical applications. This is an improvement to the conventional solvothermal method which results in heterogenous particles. For example, RT-COF-1 synthesized in this work is a promising nanocarrier for loading lonidamine for selective tumor treatment via chemotherapy. It is believed that the concept of photocatalytic-cascade COF synthesis expands the scope for imine-linked COFs and significantly enriches the nanoscale COF synthetic methodology.

Automated summary

A method for constructing imine-linked COFs through photocatalytic oxidation and imine condensation steps is reported, which can be easily scaled up and results in uniform particle size COFs suitable for biomedical applications. The concept of photocatalytic-cascade COF synthesis enriches the nanoscale COF synthetic methodology.