H-2 AND PT-195 NMR-STUDIES OF MOLECULAR AND ELECTRON-SPIN DYNAMICS INPARAMAGNETIC [CU(H2O)(6)][PTCL6]

The temperature dependences of H-2 and Pt-195 NMR spectra and the spin -lattice relaxation time T-1 were measured for [Cu(H2O)(6)][PtCl6]. Fr om the simulation of H-2 NMR spectra, the jump rate of 180 degrees fli ps of the water molecules (k), the nuclear quadrupole interaction para meters (e(2)Qq/h, eta) and the electron-nucleon dipolar interaction pa rameter (nu(D)) were obtained. By measuring H-2 T-1, k was estimated i n the temperature range where the spectrum is insensitive to the motio n of the water molecules. Above the phase transition temperature, the pre-exponential factor k(0) = 8 x 10(11) s(-1) and the activation ener gy E-a = 15 kJ mol(-1) for 180 degrees flips of the water molecules we re obtained from the spectral simulation and T-1. Pt-195 NMR spectra s howed an axially symmetric and unsymmetric powder pattern of the chemi cal shift anisotropy at the high and low temperature phase, respective ly. For the deuterated compound, the correlation ti mes of the electro n spin in Cu2+ were estimated from Pt-195 T-1 and the activation energ y for jumping between the different configurations of Jahn-Teller dist ortion Delta = 200 K was obtained.