The temperature dependence of deuteron NMR spectra of the fully deuter
ated manganese ion cluster nanomagnet Mn12O12-acetate has been measure
d. Two sets of deuteron peaks have been observed which both shift towa
rds lower fields with decreasing temperature. The strongly shifted pea
k is associated with the deuterons of the four D2O molecules which are
directly attached to the Mn core. The less shifted peak is due to the
-CD3 deuterons, which are three bonds away from the oxygen that is at
tached to Mn ions, as well as to the solvated D2O and CD3COOD molecule
s. The results imply that the unpaired spin density extends over the w
hole molecular cluster rather than being concentrated at the Mn ions.