Chlorine-35 NQR and¹H NMR study of guest structure and dynamics in the thiourea-hexachloroethane inclusion compound

Abstract

Atom-atomic potential calculation of the channel non-stoichiometric thioureahexachloroethane 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 results of 35 Cl NQR and 1 H NMR measurements of thioureahexachloroethane, [2.95(NH 2 ) 2 CS]C 2 Cl 6 , in the temperature range from 7.5 to 90 K, which confirm 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 commensurate regions, while the third resonance, showing an anomalous behaviour, was attributed to the guest molecules in the domain wall. The observed structure results from the different periodicity of the guest and host substructures and shows a difference from conventional continuum models of the incommensurate state. Propagation motion of the domain wall over the channel is discussed.