Metal-π Interaction-Enhanced Electrochemiluminescence via U-Shaped Schiff Base Luminophores for Ultrasensitive...

The advancement of electrochemiluminescence (ECL) sensing has been increasingly restricted by the lack of rationally designed luminophores that simultaneously support efficient charge transfer, excited-state stability, and catalytic amplification. Herein, we report a Fe(II)-coordinated U-shaped Schiff base luminophore (Fe-PDLILUM) that achieves significantly enhanced ECL via synergistic metal-π interactions and topological rigidification. This luminophore is synthesized through imine-bridged conjugation between isoluminol and 1,10-phenanthroline-2,9-dicarboxaldehyde, forming an extended π-delocalized framework that promotes intramolecular charge transport and suppresses nonradiative decay. Fe²⁺ coordination further stabilizes the excited state and facilitates reactive oxygen species (ROS) generation, resulting in a 4-fold increase in ECL intensity compared to unmodified isoluminol. On applying to clindamycin (CLM) sensing, this system delivers an ultralow detection limit of 1.62 nM and a wide linear range of 5 nM to 30 μM, with excellent selectivity and robustness in complex matrices including river water and milk. This work establishes a modular and mechanism-driven strategy for constructing high-performance ECL emitters, offering a versatile platform for antibiotic monitoring in both clinical and environmental applications.