Fluorescent Lanthanide Anthracene Frameworks for High‐Resolution Cellular Imaging and Iron(II) Sensing

Three fluorescent lanthanide (La/Dy) anthracene frameworks were synthesized under solvothermal conditions using the semi-flexible anthracene-derived zwitterionic ligand 9,10-bis[[(4-carboxylato)pyridin-1-ium-1-yl]methyl]anthracene (BCPA): {[Dy(BCPA)₂(H₂O)₄]·Cl₃·DMF·EtOH·(H₂O)₃·(S)}_n (MOF-1), {[La(BCPA)₂(H₂O)]·Cl₃·(H₂O)₂·(S)}_n (MOF-2), and {[Dy(BCPA)(H₂O)₄]·Cl₃·(S)}_n (MOF-3), where S represents disordered solvent molecules. MOF-1 features a 1D chain architecture, whereas MOF-2 and MOF-3 crystallize into 3D frameworks. MOF-1 exhibits nanometer-scale particle size, strong photoluminescence, and high solubility in water/DMSO mixtures, making it an efficient probe for high-resolution live-cell imaging in HCT-15 cells with minimal cytotoxicity. In contrast, porous 3D architectures of MOF-2 and MOF-3, combined with their robust fluorescence, enable sensitive Fe² ⁺ detection, displaying higher quenching efficiency and lower detection limits than MOF-1. Therefore, despite their identical chemical compositions, the dimensionality-induced differences in morphology and surface accessibility provide a rational basis for the observed divergence in biological imaging versus chemical sensing applications.