MOLECULAR MOTIONS IN THE NOVEL PLASTIC PHASE OF DECAMETHYLFERROCENE STUDIED BY H-1-NMR AND THERMAL MEASUREMENTS

The (1)HNMR spin-lattice relaxation time and second moment of the reso nance line-width in solid decamethylferrocene [(CH3)(5)C]Fe-2 have bee n measured in temperature ranges 85-540 K, and 300-540 K respectively. The presence of two solid-solid phase transitions were revealed at 39 7 +/- 1 K and 501 +/- 2 K, by differential scanning calorimetry, Phase I obtainable above 501 K was shown to be a plastic phase, where the i sotropic molecular rotation and the translational self-diffusion rapid ly take place. In the low-temperature Phases II and III, excitations o f the CH3 reorientation, the uniaxial reorientation of the whole molec ule about its C-5 axis and the nutation of this C-5 axis were observed .