Two helium atoms inside fullerenes: probing the internal magnetic field in C60(6-) and C70(6-).
A 3He NMR resonance of C606- containing He is assigned to He2@C606-, thus showing that C60 can also accommodate two helium atoms. The ratio of the di-helium compound relative to the mono- is 1:200, 10 times lower than the equivalent counterpart of C70. The 3He NMR chemical shift of He2@C606- is 0.093 ppm downfield from the already known resonance of He@C606-. In the reduced endohedral mono- and di-helium C70, the 3He NMR chemical shift of He2@C706- is 0.154 ppm upfield from the peak of He@C706-.
Department of Organic Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Tamar
T
Sternfeld
Roy E
RE
Hoffman
Martin
M
Saunders
R James
RJ
Cross
M S
MS
Syamala
Mordecai
M
Rabinovitz