Chlorine-35 NQR and H-1 NMR study of guest structure and dynamics in the thiourea-hexachloroethane inclusion compound

Atom-atomic potential calculation of the channel non-stoichiometric thioure a-hexachloroethane inclusion compound shows that the structure of the guest sublattice comprises two types of finite molecular chain, having different structure and separated by domain walls. In the present paper we present r esults of Cl-35 NQR and H-1 NMR measurements of thiourea-hexachloroethane, [2.95(NH2)(2)CS]C2Cl6, in the temperature range from 7.5 to 90 K, which con firm this model and show the existence of such a state at least below 60 K. Two resonances in the NQR spectra were assigned to the two nearly commensu rate regions, while the third resonance, showing an anomalous behaviour, wa s attributed to the guest molecules in the domain wall. The observed struct ure results from the different periodicity of the guest and host substructu res and shows a difference from conventional continuum models of the incomm ensurate state. Propagation motion of the domain wall over the channel is d iscussed.