NMR spectroscopy in environmental chemistry: 1H and 13C NMR chemical shift assignments of chlorinated dibenzothiophenes based on two-dimensional NMR techniques and ab initio MO and DFT/GIAO calculations

✍ Scribed by Erkki Kolehmainen; Jari Koivisto; Vladimir Nikiforov; Mikael Peräkylä; Kari Tuppurainen; Katri Laihia; Reijo Kauppinen; Sergei A. Miltsov; Vladimir S. Karavan

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 71 KB
• Volume: 37
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199910)37:10<743::aid-mrc532>3.0.co;2-z

✦ Synopsis

1 H and 13 C NMR spectra for seven chlorinated dibenzothiophenes (DBTs) were measured. Complete 1 H and 13 C NMR chemical shift assignments for 2, 8-and 3,7-dichloro-and 2,3,6,8-, 2,3,7,8-and 2,4,6,8-tetrachloro congeners are based on z-gradient selected inverse (proton detected) two-dimensional heteronuclear chemical shift correlation experiments, 1 H, 13 C HMQC and HMBC. For 1,2,3,4,6,7,8-heptachloro-DBT and octachloro-DBT, where polarization transfer techniques from proton to (all) carbons are not possible, the 13 C NMR chemical shift assignments are based on theoretical calculations using ab initio MO and DFT/GIAO methods at the HF/6-311G Ł and BPW91/6-311G Ł levels. The observed HMBC correlations for the heptachloro congener are in good agreement with a theoretically predicted shift order, providing evidence for the reliability of the theoretical method.