An Open-Cage Fullerene That Mimics the C60H10 (5,5)-Carbon Nanotube Endcap to Host Acetylene and Hydrogen Cyanide Molecules

摘要

Treatment of the open-cage fullerene C63H4NO2(Ph)(2)(Py)(N2C6H4) (1) with methanol at 150 degrees C results in an orifice-enlargement reaction to give C69H8NO(CO2Me)(Ph)(Py)(N2C6H4) (2). The overall yield from C-60 to isolated 2 is 6.1% (four steps). Compound 2 contains a 24-membered elliptic orifice that spans 8.45 angstrom along the major axis and 6.37 angstrom along the minor axis. The skeleton of 2 resembles the hypothetic C60H10 (5,5)-carbon nanotube endcap. The cup-shaped structure of 2 is able to include water, hydrogen cyanide, and acetylene, forming H2O@2, HCN@2, and C2H2@2, respectively. The molecular structures of H2O@2 and HCN@2 have been determined by X-ray crystallography. The (HNMR)-H-1 spectra reveal substantial upfield shifts for the endohedral species, such as =-10.30 (for H2O), -2.74 and -14.26 (for C2H2), and -1.22ppm (for HCN), owing to the strong shielding effects of the fullerene cage.