Supramolecular Nanostructures of Boron-Nitrogen-Embedded Cycloparaphenylene Triradicals: Tuning Charge Transfer and...

Supramolecular complexes of cycloparaphenylene (CPP) and fullerene have been widely studied due to their fascinating topological structures and unique optoelectronic properties. Herein, we theoretically investigate a series of nanostructures, where boron and/or nitrogen atoms substitute the central carbon atom in a through-space conjugated multiphenalenyl triradical (B_nN_3-n-TPP, n = 0, 1, 2, 3, Type I), further constructing carbon nanorings (B_nN_3-n-TCPP, Type II), supramolecular fullerenes (C₆₀@B_nN_3-n-TPP, Type III), and supramolecular nanostructures (C₆₀@B_nN_3-n-TCPP, Type IV). The results show that the supramolecular assembly and the number of nitrogen atoms strongly regulate charge transfer and second-order nonlinear optical (NLO) properties. Specifically, Type II carbon nanorings exhibit excellent intramolecular charge transfer (CT) between B_nN_3-n-TPP and CPP unit, while Types III and IV display both inter- and intramolecular CT, demonstrating the effectiveness of the supramolecular design. Notably, the first hyperpolarizabilities (β_tot) of C₆₀@B₂N-TCPP (6.13 × 10⁴ au) and C₆₀@N₃-TCPP (6.96 × 10⁴ au) are enhanced by a self-assembly strategy, while that of C₆₀@BN₂-TCPP (4.96 × 10⁴ au) decreases likely due to opposing directions of inter- and intramolecular CT. This work highlights the potential of carbon nanorings and supramolecular complexes for the design and synthesis of advanced optoelectronic devices, as well as high-performance NLO materials.