AN NQR STUDY OF INCLUSION-COMPOUNDS FORMED BETWEEN SMALL CHLORINE-CONTAINING MOLECULES AND BIS(N-ALKYLIMIDAZOLIDINE-2-THIONE)CU(I) HALIDE-COMPLEXES

Twenty-five inclusion complexes formed by bis(N-alkylimidazolidine-2-t hione)cuprous halides with the small, chlorine-containing guest molecu les CCl4, CHCl3, CH2Cl2, CH3CCl3 or C2H2Cl2, have been prepared. Their Cu-63 and Cl-35 NQR spectra have been measured over the temperature r ange 77-300 K. For the corresponding bromides the Br-79 and/or Br-81 s pectra have also been investigated. The studies reveal the number and symmetry of different inclusion site. The onset of rapid reorientation of the guest molecules is indicated by the fading out of their NQR si gnals between 77 and 300 K, whereas the resonances from the host molec ules usually persist throughout this temperature range. However, as ev idenced by discontinuities in the temperature-dependence of the NQR fr equencies of the hosts, sixteen of the complexes show one or more phas e-changes in this temperature-range.