A Supramolecular Naphthalene Diimide Radical Anion with Efficient NIR‐II Photothermal Conversion for E. coli‐Responsive Photothermal Therapy

We report a supramolecular naphthalene diimide (NDI) radical anion with efficient NIR‐II photothermal conversion for E. coli‐responsive photothermal therapy. The supramolecular radical anion (NDI‐2CB[7])·‐, which is obtained from the E. coli‐induced in‐situ reduction of NDI‐2CB[7] neutral complex, formed by the host‐guest interaction between an NDI derivative and cucurbit[7]uril (CB[7]), exhibits unexpectedly strong NIR‐II absorption and remarkable photothermal conversion capacity in aqueous solution. The NIR‐II absorption is caused by the self‐assembly of NDI radical anions to form supramolecular dimer radicals in aqueous solution, which is supported by theoretically predicted spectra. The (NDI‐2CB[7])·‐ demonstrates excellent NIR‐II photothermal antimicrobial activity (> 99%). This work provides a new approach for constructing NIR‐II photothermal agents and non‐contact treatments for bacterial infections.