Formulating the Relationship Between Intermolecular Interactions and Photodynamic Effects Based on the Optical Regularity Exhibited by Rare Earth‐BODIPY Crystalline Frameworks System

Abstract This research commenced with an exploration of how metal nodes in metal‐organic frameworks (MOFs) influence photodynamic therapy (PDT) outcomes. Ultimately, it is revealed that intermolecular interactions are the core mechanism determining the optical properties and PDT efficacy of MOFs. An advanced system of MOFs based on the integration of twelve rare earth ions (RE 3+ ) with boron dipyrromethene (BODIPY)‐derived ligands is reported. Intriguingly, this series of MOFs exhibits a reverse relationship between the radius of RE 3+ and PDT efficacy. Single‐crystal X‐ray diffraction analyses along with theoretical calculations indicate that varying RE 3+ results in a spatial displacement of the ligands along the dipole direction, diminishing electrostatic (dipole–dipole) interactions while enhancing dispersion (π–π) interactions, thereby enhancing the generation of triplet excitons. Consequently, a novel parameter, A e‐v = E vdW / E int × 100%, is proposed to quantify the interplay between non‐radiative energy dissipation via electrostatic interactions and efficient energy utilization in generating singlet oxygen through dispersion interactions. Furthermore, with consistent acoustic sensitivity aligned with the sonoluminescence mechanism, RE‐DCBs are employed in sono‐photodynamic cancer therapy, attaining significant therapeutic results in tumor treatment during in vivo experiments.