The synthesis of antiaromatic molecules with intense near-infrared (NIR) absorption is challenging because of their inherently forbidden HOMO–LUMO transitions. In this research, we have synthesized anthracene-fused and anthanthrene-fused boron dipyrromethene (BODIPY) with different substituents through oxidative cyclodehydrogenation. These BODIPY-fused nanographenes exhibited distinct antiaromatic characteristics, supported by 1H NMR analysis and theoretical calculations. These nanographenes exhibit a narrow electro-chemical HOMO–LUMO energy gap down to 0.84 eV and NIR absorption capability up to 1600 nm. Transient absorption spectrosco-py revealed the rapid decay of their excited state. By encapsulating 3a and 4b with amphiphilic polymer, water-soluble nanoparticles 3a-NPs and 4b-NPs were produced, which exhibit outstanding photostability and a high photothermal conversion efficiency of 68% and 57%, respectively. These findings demonstrated that the BODIPY-fusion strategy effectively grants antiaromaticity and NIR absorption properties to nanographenes.
Wang et al. (Fri,) studied this question.