Synthesis of Defective Wheel‐Shaped Nanographdiynes

Abstract The synthesis and optical properties of wheel‐shaped nanographdiynes that has lost some butadiyne spokes were reported. These defective wheel‐shaped nanographdiynes possess butadiyne‐bridged metacyclophanes with para‐bis(phenylbutadiynyl)‐benzene units as the axis. The optimized geometries of the defective wheel‐shaped nanographdiynes along with their vibrational spectra, HOMO and LUMO orbitals were calculated at B3LYP/6‐311G(d,p) level. HOMO and LUMO orbitals are delocalized mainly over the para‐bis(phenylbutadiynyl)‐benzene axis, with weak contribution from the attached ethynyl units. The π‐conjugation extension and quantity increase of the para axis influenced the optical properties of these graphdiyne substructures, leading to the change of bandgap from 2.88 eV to 2.56 eV as reflected by optical spectroscopy. The defective wheel‐shaped nanographdiynes lost the characteristic intensive sharp absorption peak at low energy region, which indicated that the fusion of adjacent dehydrobenzo [18] annulenes are crucial for the bulk properties of graphdiyne.