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The 1H NMR spectrum and the crystal structure of HCDBCO [(1R,2R,5R,6R,9S,10S)-5,6-dibromo-1,10,11,12,13,13-hexachlorotricyclo[8,2,1,02,9]-tridec-11-ene)] are reported. The measured dihedral angles from the X-ray structure correlate very well with those calculated from the proton–proton coupling constants indicating that the conformations in solution and in the solid state are probably very similar. Attempts at calculating the 3D model structure of HCDBCO only produced a very poor match between the measured dihedral angles between vicinal protons and the observed proton–proton coupling constants from the 1H NMR spectrum. GC/MS analysis with an injector temperature of 250°C produced minor amounts of debrominated HCDBCO. Reducing the temperature to 200°C eliminated this problem. [Copyright &y& Elsevier]

Abstract: Very little data is available about the presence of the brominated flame retardant, DBDPE, in the environment. This study reports the characterization of [13C14]-decabromodiphenylethane and the use of this surrogate standard to positively identify and quantify the presence of DBDPE in sewage sludge samples. The large difference in response factors between BDE-209 and DBDPE predicates the use of [13C14]-decabromodiphenylethane as a surrogate standard to improve the accuracy when determining the levels of DBDPE in environmental samples. [Copyright &y& Elsevier]

Technical perfluorooctanesulfonate (PFOS) and its derivatives, such as perfluorooctanesulfonamide (PFOSA), are not clean compounds but, instead, complex mixtures of linear and branched isomers, and other compounds including sulfonate homologues. Questions have been raised as to whether the linear and the branched isomers behave differently in the environment. However, little is known about the physical properties or the finer details of the structures of the individual branched isomers. This study sought an effective computational method to model the preferred conformations of PFOS derivatives, and the energy differences between them and to determine if these results can be used to explain the temperature dependence of their NMR spectra. Good predictions of the 19F chemical shifts were obtained for some PFOSA-type molecules with a computational approach [B3LYP-GIAO/6-31++G(d,p)//B3LYP/6-31G(d,p)] that is relatively inexpensive. Large 5JFF couplings found in one of the branched isomers could be rationalized on the basis of the relevant F–F distances in the optimized structure. At low temperatures, the splitting observed in the NMR spectrum at C-1 for these sulfonamides can be explained by the existence of the two conformers predicted by the computations. [Copyright &y& Elsevier]