  The molecular conductors [M(tmdt)$_2$] (M=Ni, Pt) consisting of single
molecular species are investigated with $^{13}$C NMR and $^1$H NMR. The
temperature dependences of $^{13}$C NMR shift and relaxation rate provide
microscopic evidences for the metallic nature with appreciable electron
correlations. Both compounds exhibit an anomalous frequency-dependent
enhancement in $^1$H nuclear spin-lattice relaxation rate in a wide temperature
range. These observations signify the presence of extraordinary molecular
motions with low energy excitations.

Materials Science