Multimodal Fluorescent MOF@BODIPY Platform: Bridging Sensing and Mechanistic Insight

Hybrid metal-organic frameworks (MOFs) that integrate organic chromophores constitute powerful platforms for optical sensing by combining structural order with tunable photophysics. Incorporating photoresponsive chromophores into MOFs enables sensitive probing of guest-framework interactions through well-defined luminescent signatures. Herein, we present a hybrid luminescent platform, based on a UiO-66-NH₂ MOF covalently functionalized with BODIPY dyes (MOF@BODIPY), designed for advanced optical sensing. The material integrates two independent excitation channels: selective activation of the MOF scaffold and the BODIPY chromophore at 400 and 500 nm, respectively. This dual-channel architecture enables simultaneous quantitative detection and mechanistic insight, bridging sensing performance with fundamental photophysics. Under BODIPY excitation, MOF@BODIPY exhibits strong fluorescence quenching response toward Fe³⁺ ions, achieving a limit of detection as low as 0.07 µM. Complementary excitation of the MOF scaffold reveals fluorescence enhancement, providing mechanistic evidence of coordination-driven suppression of nonradiative pathways. Time-resolved fluorescence spectroscopy confirms static quenching at the dye level and dynamic modulation within the MOF framework, highlighting synergistic interactions between both components. The hybrid's low-cost synthesis, high sensitivity, and dual optical functionality positions MOF@BODIPY as a versatile proof-of-concept for multimodal sensing platforms and highlights its potential for next-generation optical sensors in environmental applications.