Boron‐Difluoride Curcuminoid Dendrimers as Organic Near‐Infrared Photothermal Materials

Organic molecules with absorption in the near‐infrared (NIR) region and efficient photothermal conversion are desirable for applications in photothermal therapy due to their synthetic tunability and improved biocompatibility. In this work, boron‐difluoride curcuminoid dendrimers with carbazole‐based arylamine units were developed with NIR optical bandgaps and high rates of nonradiative decay to promote photothermal conversion. The resulting compounds BF 2 ‐2TTAC and BF 2 ‐2TMAC were coprecipitated into water‐dispersible nanoparticles in the presence of a DSPE‐PEG2k surfactant. The photothermal properties of these nanoparticles were investigated under NIR irradiation, with photothermal conversion efficiencies of (66 ± 5)% and (58 ± 3)% for BF 2 ‐2TTAC and BF 2 ‐2TMAC NPs , respectively. This work leverages the incorporation of strong donor and acceptor units to favor NIR absorption while incorporating dendritic donors to enhance intramolecular motions that favor nonradiative decay. These results also demonstrate how strategies commonly used for designing materials that exhibit thermally activated fluorescence can be used to achieve high‐performance photothermal materials.