Chi-Shian Chen

Encapsulation of Formaldehyde and Hydrogen Cyanide in an Open-Cage Fullerene

Reaction of C63 NO2 (Ph)2 (Py) (1) with o-phenylenediamine and pyridine produces a mixture of C63 H4 NO2 (Ph)2 (Py)(N2 C6 H4 ) (2) and H2 O@2. Compound 2 is a new open-cage fullerene containing a 20-membered heterocyclic orifice, which has been fully characterized by NMR spectroscopy, high-resolution mass spectrometry, and X-ray crystallography. The elliptical orifice of 2 spans 7.45 Å along the major axis and 5.62 Å along the minor axis, which is large enough to trap water and small organic molecules. Thus, heating a mixture of 2 and H2 O@2 with hydrogen cyanide and formaldehyde in chlorobenzene affords HCN@2 and H2 CO@2, respectively. The (1) H NMR spectroscopy reveals substantial upfield shifts for the endohedral species (δ=-1.30 to -11.30 ppm), owing to the strong shielding effect of the fullerene cage.

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

Treatment of the open-cage fullerene C63 H4 NO2 (Ph)2 (Py)(N2 C6 H4 ) (1) with methanol at 150 °C results in an orifice-enlargement reaction to give C69 H8 NO(CO2 Me)(Ph)(Py)(N2 C6 H4 ) (2). The overall yield from C60 to isolated 2 is 6.1 % (four steps). Compound 2 contains a 24-membered elliptic orifice that spans 8.45 Å along the major axis and 6.37 Å along the minor axis. The skeleton of 2 resembles the hypothetic C60 H10 (5,5)-carbon nanotube endcap. The cup-shaped structure of 2 is able to include water, hydrogen cyanide, and acetylene, forming H2 O@2, HCN@2, and C2 H2 @2, respectively. The molecular structures of H2 O@2 and HCN@2 have been determined by X-ray crystallography. The 1 H NMR spectra reveal substantial upfield shifts for the endohedral species, such as δ=-10.30 (for H2 O), -2.74 and -14.26 (for C2 H2 ), and -1.22 ppm (for HCN), owing to the strong shielding effects of the fullerene cage.