Highly Sensitive and Reliable NIR Luminescent Sensing Toward Nitro‐Aromatic Antibiotics in Water

Near‐infrared (NIR) light features less photon scatter and deeper penetration, thereby providing a sensitive and reliable platform for qualifying and quantifying trace organic contaminants in water medium. Herein, a lanthanide/β‐diketone complex, Yb(dmh)3(phen) (dmh = 2,6‐dimethyl‐3,5‐heptanedione, phen = 1,10‐phenanthroline), is synthesized and performs characteristic NIR luminescence of Yb3+ ions. The outstanding photophysical properties result from the combination effects of excited‐state inter‐ligand charge transfer, ligand‐to‐metal energy transfer, and high structural symmetry. Noteworthily, this NIR luminophore exhibits state‐of‐the‐art sensitivity toward nitro‐aromatic antibiotics in water. The limits of detection are lower to sub‐nanomolar level for nitroimidazoles (metronidazole 0.18 nM; dimetridazole 0.23 nM; ornidazole 0.28 nM) and even picomolar level for nitrofurans (nitrofurantoin 43 pM; nitrofurazone 46 pM). This exciting sensitivity attributes to photo‐induced electron transfer and inner filter effect between sensor and adsorbed analytes. The sensor is also capable of distinguished stability, selectivity, competitiveness, and anti‐interference, which makes it far better suited to the commercial application. The successfully developed technique of NIR luminescence sensing extends the platform of optical devices and sensing materials, being of practical value in monitoring water quality. Developing advanced functional materials to qualify and quantify organic contaminants is urgent but challenging. Herein, NIR luminescence chem‐sensor toward nitro‐aromatic antibiotics in water system has been investigated and realized. It is achieved that state‐of‐the‐art sensitivity, good selectivity, excellent competitiveness, and anti‐interference. The mechanism pertaining to photophysical property and sensing behavior has been systematically analyzed, based on the perspective of charge and energy transfer.