Quadrupole relaxation enhancement and polarisation transfer in DMSO solution of [Bi(NO 3 ) 3 (H 2 O) 3 ]*18-crown-6 in solid state

1H spin-lattice relaxation studies have been performed for pure [Bi(NO3)3(H2O)3]*18-crown-6 in powder and its solution in dimethyl sulfoxide (DMSO). The experiments have been carried out in the frequency range of 10 kHz–30MHz and the temperature range of 240–277 K; at 277 K the solution is already frozen. The 1Hrelaxation of pure [Bi(NO3)3(H2O)3]*18-crown-6 has been interpreted in terms of three dynamical processes. Quadrupole Relaxation Enhancement effects have been observed in the frozen DMSO solution of [Bi(NO3)3(H2O)3]*18-crown-6. The specific mechanisms of the 1H spin- lattice relaxation enhancement have been discussed distinguishing between effects caused by time independent (residual) and fluctuating 1H-209Bi dipole-dipole interactions.