AN NMR-STUDY OF HE-2 INSIDE C-70

A peak in the helium NMR spectrum of He-3 labeled C-70 is assigned to molecules containing two helium atoms. The concentration of the diheli um species is about 1/20th that of molecules containing a single heliu m, and the helium shift of this new species is 0.014 ppm (5.6 Hz) down field from the resonance for molecules containing one helium. Mass spe ctrometry confirms the presence of dilabeled molecules. A Hirsch-Binge l transformation of the C-70 to a malonate diethyl ester increases the chemical shift difference between the mono- and dihelium species.