Structure-Property Relationships in Mg-MOFs: Dimensional Effects on the Electrocatalytic Detection of Dopamine

The well-defined crystalline structures of metal-organic frameworks (MOFs) offer a versatile platform for investigating structure-property relationships in electrocatalysis. Herein, we report the synthesis of two magnesium-based MOFs (Mg-MOFs, MOF-1 and MOF-2) constructed from Mg2+ ions and a tetraphenylethylene (TPE)-based fluorinated ligand (H4tmpe-F). Through precise modulation of solvothermal conditions, distinct structural dimensionalities were achieved, allowing for a comparative study of their electrochemical behaviors. When employed as electrocatalysts for dopamine (DA) oxidation, the MOFs exhibited dimension-dependent activity. Notably, MOF-2, featuring a 2D framework, demonstrated significantly enhanced electrocatalytic performance compared to MOF-1, which features a 1D chain-like structure, yielding a low detection limit of 12.9 nM and a high sensitivity of 1759.7 μA·mM-1·cm-2. To elucidate the origin of this reactivity difference, density functional theory (DFT) calculations were performed. The theoretical results reveal that the specific structural arrangement of MOF-2 facilitates stronger adsorption affinity toward DA molecules and optimizes the reaction pathway energetics. This work highlights the critical role of structural dimensionality in tuning the electrochemical properties of Mg-MOFs and provides a fundamental understanding of their catalytic mechanisms at the molecular level.