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Abstract

2H‐nuclear magnetic resonance was applied to single crystals of the clathrate of Dianin’s compound with ethanol as a guest. The hydroxyl groups of both the host lattice and the guest were deuterated. The temperature dependences of the 2H spectra and of the quadrupole coupling tensors of the host lattice deuterons provide evidence that these deuterons carry out jumps between two unequally populated sites. These jumps may be visualized as approximate rotations of the hydroxyl groups about the C–O bonds. The occupancies of the two sites were measured and found to follow a Boltzmann distribution at T>145 K. At lower temperatures the minority sites are overpopulated. The temperature dependence of the jump rate was determined by line shape analyses and relaxation time measurements. From the absence of dipolar fine structure in the 2H spectra recorded for specially chosen crystal orientations it is concluded that groups of six hydroxyl units carry out their rotational jumps in a concerted manner.