3He NMR spectroscopy

Abstract NMR spectroscopy is so far the only analytical technique that has been used to get a detailed structural characterization of hydrogenated fullerenes. A substantial amount of information derived from different NMR experiments can thus be found in the literature for a number of fullerenes hydrogenated to various degrees. These studies have benefitted from the fact that chemical shifts of II and 13C and in some cases also 3He can be used to obtain structural information of these compounds. Such results, together with discussions about different NMR experiments and general considerations regarding sample preparations, are summarized in this chapter. The unique information, both structural and physicochemical, that can be derived from different NMR experiments ensures that this technique will continue to be of central importance in characterization of hydrogenated fullerenes. 

Heymann et al. [255] and Smith et al. [256] reported the synthesis of C70O 82 by photooxygenation. Irradiation of an oxygenated toluene solution of C70 and rubrene as a sensitizer resulted in the formation of a nearly 1 1 mixture of two C70O isomers 82a and 82b that can not be separated (Fig. 31). The structures of 82a and 82b were elucidated by UV-vis spectroscopy, 13C-NMR studies as well as 3He NMR studies. No evidence for the formation of isomers 82c and 82d was found. 

Group 18. - A 3He NMR study has been made of line-broadening in solid 3He-4He mixtures below 50 mK.571 2H NMR spectroscopy was used to study impurity-helium solids prepared by injecting deuterium atoms and mole-cules into superfluid He. Pulsed He NMR data were reported for solid He in a silver sinter down to temperatures of 400 pK.573 He NMR was used to characterise 3He nanoclusters embedded in h.c.p. 4He.574 Ferromagnetism of two-dimensional solid 3He has been investigated by SQUID NMR.575... 

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