NMR spectroscopy in environmental chemistry: H-1 and C-13 NMR parameters of tricyclic polychlorinated C-10 hydrocarbons and their oxy derivatives based on two-dimensional NMR techniques

Two-dimensional homo- and heteronuclear NMR chemical shift correlation tech niques were applied in the characterization of five tricyclic polychlorinat ed Clo hydrocarbons, chlordene (1), heptachlor (2), trans-nonachlor (3), al pha-chlordene (4) and gamma-chlordene (5), which are spread globally in the environment owing to their use as insecticides. Approximate and partly con tradictory H-1 and C-13 NMR chemical shifts reported in the literature were corrected in this work. The chemical shift assignments of 1-5 were based o n DQF COSY, HMQC and HMBC experiments. In addition, an INADEQUATE experimen t was needed to ascertain the 13C chemical shifts assignment of 2. The (n)J (H,H)s of 1-5 were solved by computer-assisted spectral analyses. Further, complete H-1 and C-13 NMR parameter sets of three oxy derivatives, heptachl or exo-epoxide (6), 1-exo-hydroxychlordene (7) and its acetate (8), were al so determined. Compounds 7 and 8 were synthesized to be used as model compo unds, and their NMR parameters are reported for the first time. By using so lvent susceptibility matched symmetrical micro-MMR tubes and HMQC and HMBC experiments, 1-5 can be reliably characterized at submilligram levels by th eir H-1 and C-13 NMR parameters with a 500 MHz (11.8T) spectrometer and a 5 mm diameter standard probehead. Copyright (C) 1999 John Wiley & Sons, Ltd.