H-1, C-13 NMR-SPECTROSCOPY AND CONFORMATIONAL PROPERTIES OF 18 HALOGENATED DIPHENYL ETHERS

18 Polyhalogenated diphenyl ethers (DEs) were synthesized and their H-1 and C-13 NMR spectra measured and analyzed. As far as we know, most NMR data are reported for the first time. The assignments of the H-1 and C-13 NMR spectra of one congener were ascertained by 2-D C-13-H-1 COSY measurements. C-13 chemical shift differences between ortho and meta positions indicate the varying conjugational extent of the ether oxygen with the phenyl groups. All theoretical and experimental results show that the coplanarity of DEs is impossible. Thermodynamical and kinetical considerations suggest the free internal motion of DEs around their C-O bond at ambient temperatures.