Abstract |
Chlorine nuclear quadrupole resonance (NQR) spectrometry has been employed to demonstrate the difference in the chemical environment of the Cl atoms in several organochlorine compounds commonly used as pesticides. Correlations between resonance frequency and structure have been made in four isomers of 1,2,3,4,5,6-hexachlorocyclohexane (HCH) and in certain cyclodiene chlorinated insecticides including 1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-1,4-endo, exo-5,8-dimethanonaphthalene (aldrin), 1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro-1,4-endo, exo-5,8-dimethanonaphthalene (dieldrin), 1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene (heptachlor), 1,4,5,6,7,8,8-heptachloro-2,3-epoxy-2,3,3a,4,7,7a-hexahydro-4,7-methanoindene (heptachlor epoxide), 1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro-1,4-endo, endo-5,8-dimethanonaphthalene (endrin), and cis-1,2,4,5,6,7,8,8-octachloro-2,3,3a,4,7,7a-hexahydro-4, 7-methanoindene (alpha-chlordane). Assignment of signals to specific chlorine atoms has been made utilizing spectra-structure correlation charts and other data. Some of the problems encountered in the interpretation of NQR spectra are discussed. |