FERROCENE MOLECULAR-REORIENTATION IN THE (THIOUREA)3.FERROCENE INCLUSION COMPOUND AS STUDIED BY H-2 NMR-SPECTROSCOPY

The molecular reorientational dynamics of ferrocene included in the (thiourea)3.ferrocene complex have been studied by C-13 CP/MAS NMR and H-2 NMR spectroscopy. Analysis of the H-2 NMR line shapes has allowed delineation of two distinct reorientational processes among the four distinguishable orientations of ferrocene suggested to be populated in this inclusion compound. Kinetic parameters have been estimated as E(a) = 6.4 +/- 0.5 kJ mol-1 with A = (2.15 +/- 0.5) x 10(7) s-1 for the direct interchange between the three orientations perpendicular to the host channel axis, and E(a) = 10.1 +/- 1.0 kJ mol-1 with A = (1.5 +/- 0.6) x 10(8) s-1 for parallel-perpendicular orientational interchange. These results are compared with rates found from 57Me Mossbauer studies and C-13 NMR spectra of powder and oriented samples.