Bowl-Shaped Anthracene-Fused Antiaromatic Ni(II) Norcorrole: Synthesis, Structure, Assembly with C₆₀, and Photothermal Conversion

Abstract

The synthesis of bowl-shaped antiaromatic molecules is challenging because the molecular distortion further destabilizes these already inherently reactive molecules. Here, we report the synthesis and properties of bowl-shaped fused anthrylnorcorroles that exhibit near-infrared (NIR) absorption reaching 1900 nm. The oxidation of 𝘮𝘦𝘴𝘰-anthryldibromodipyrrin provides fused anthryldibromodipyrrin, which was converted to the fused mono- and bisanthrylnorcorroles through Ni(0)-mediated intramolecular coupling with a bis(dibromodipyrrin) Ni(II) complex. Single-crystal X-ray diffraction analyses revealed bowl-shaped structures for the fused mono- and bisanthrylnorcorroles, which enables them to act as suitable receptors for C₆₀ with bonding constants of 2.89×10³ M⁻¹ and 1.59×10³ M⁻¹, respectively. The formation of a 1 : 1 complex between the fused monoanthrylnorcorrole and C₆₀ was confirmed by single-crystal X-ray diffraction analysis. The effective expansion of the π-conjugation through the triple fusion of the norcorrole with the anthracene units substantially enhances the near-infrared absorption bands, which endows these anthrylnorcorroles with effective photothermal conversion.