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 resonance line-width in solid decamethylferrocene [(CH3)(5)C]Fe-2 have been measured in temperature ranges 85-540 K, and 300-540 K respectively. The presence of two solid-solid phase transitions were revealed at 397 +/- 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 isotropic molecular rotation and the translational self-diffusion rapidly take place. In the low-temperature Phases II and III, excitations of the CH3 reorientation, the uniaxial reorientation of the whole molecule about its C-5 axis and the nutation of this C-5 axis were observed.