Dual Regulation\nof Energy/Electron Transfer in MOF@COP\nHeterojunctions through Ingenious Molecular Engineering for Enhanced\nSonodynamic Cancer Therapy

Sonosensitization-mediated reactive oxygen species generation\nassociated\nwith energy and electron transfer is an essential process of sonodynamic\ntherapy. However, the development of sonosensitizers with both high\nintersystem crossing (ISC) rates and efficient carrier separation\nremains greatly challenging. Herein, we present a new scheme to construct\na class of heterojunctions (MC-R, R = −H, −OCH<sub>3</sub>, −Br) by Zr-based metal–organic framework (NU-901)\nand porphyrin-based covalent organic polymers (COPs) with different\nsubstituents. In this sonocatalytic system, the type-II heterojunction\nbased on NU-901 and COPs can effectively promote the separation of\nelectron–hole pairs, increasing the generation of superoxide\nanions, while the introduction of substituents (−OCH<sub>3</sub>, −Br) can extend the conjugation of COPs by p-π binding\nand enhance spin–orbit coupling through heavy atom effects,\nwhich could regulate the ISC process and improve the quantum yield\nof singlet oxygen. Remarkably, MC-Br as a representative MC-R exhibits\nthe best tumor inhibition efficiency in vivo.