A Porphyrin-Based 3D Metal-Organic Framework Featuring [Cu8Cl6]10+ Cluster Secondary Building Units: Synthesis, Structure Elucidation, Anion Exchange, and Peroxidase-Like Activity

Abstract

Herein, we report a rare example of cationic three-dimensional (3D) metal-organic framework (MOF) of [Cu₅Cl₃(TMPP)]Cl₅ ⋅ xSol (denoted as Cu-TMPP; H₂TMPP=meso-tetrakis (6-methylpyridin-3-yl) porphyrin; xSol=encapsulated solvates) supported by [Cu₈Cl₆]¹⁰⁺ cluster secondary building units (SBUs) wherein the eight faces of the Cl^--based octahedron are capped by eight Cu²⁺. Surface-area analysis indicated that Cu-TMPP features a mesoporous structure and its solvate-like Cl^- counterions can be exchanged by BF₄ ^-, PF₆ ^-, and NO₃ ^-. The polyvinylpyrrolidone (PVP) coated Cu-TMPP (denoted as Cu-TMPP-PVP) demonstrated good ROS generating ability, producing ⋅OH in the absence of light (peroxidase-like activity) and ¹O₂ on light irradiation (650 nm; 25 mW cm^-2). This work highlights the potential of Cu-TMPP as a functional carrier of anionic guests such as drugs, for the combination therapy of cancer and other diseases.

Keywords: Anion Exchange; Copper Halide Cluster; Drug Delivery; Metal-Organic Frameworks; Reactive Oxygen Species.