Synthesis of Nanographene-Fused Carbaporphyrin(2.1.0.1) and Its Organopalladium(II) Complex.

New nanographene ligands are indispensable for expanding the metal-doping chemistry of nanographenes. In this study, by incorporating an o-dipyrrolylbenzene unit into the bay region of an iconic nanographene, hexa-peri-hexabenzocoronene (HBC), we synthesized nanographene-fused carbaporphyrin(2.1.0.1) (1). Compound 1 displayed a nonaromatic character, as indicated by 1H NMR spectroscopy, single-crystal X-ray structure analyses, and nucleus-independent chemical shift (NICS) calculations. Additionally, 1 featured a dianionic cavity with an adj-CCNN core capable of stabilizing the PdII cation. Both the ligand and its organopalladium(II) complex adopted a distorted chair conformation. Compared to free ligand 1, complex 1·Pd showed red-shifted UV-vis absorption, aligning with the reduced electrochemical and calculated HOMO-LUMO gaps. The marked differences between 1 and previously reported HBC-fused carbaporphyrin(1.1.1.0) indicate that slight modifications to the pyrrolic unit significantly altered the electronic structure and metal-doping behavior of the nanographene ligand.