NMR evidence for the charge transfer from interstitial NO or O2 to molecule C60 in solid C60

Solid C₆₀ was stored in NO and O₂ under high pressure, and the molecule NO and O₂ were found to diffuse into the octahedral interstitial sites in its fcc crystal lattice. Their ¹³C NMR MAS spectra composed of a primary resonance at 143.7 ppm, accompanied by several minor peaks shifted downfield respectively. The spectra at various temperatures from 210 to 300 K have been measured, and the chemical shifts of the minor peaks referenced to the primary resonance versus inverse temperature show straight lines. But, the lines do not go through origin, and their intercepts are equal to 0.13 ppm or its multiple. Due to a non-zero intercept at high-temperature limit, we proposed that there is a charge transfer from NO and from O₂ to C₆₀. The quantity of the charge transferred has been calculated, that is about 0.065 q_e^- (q_e^- for the elementary charge on an electron).