Ab initio study of halogenated diphenyl ethers. NMR chemical shift prediction

Abstract

The geometries of five diphenyl ethers were fully optimized at the B3LYP/6–31G(d) level. Using HF‐ and DFT‐GIAO methods, isotropic NMR shielding tensors of these molecules were computed. The calculated 13C, 1H and 17O NMR chemical shifts are dependent on the model chemistry applied. Comparison of the calculated shifts with the experimental values revealed that B3LYP/6–31G(d,p) produced best results for proton chemical shifts, HF/6–31G(d,p) for 13C and HF/6–311 + G(2d,p) for 17O. No single method appears satisfactory for calculation of all the chemical shifts. Copyright © 2000 John Wiley & Sons, Ltd.

Characterization of siloxane copolymers by solution 17O NMR spectroscopy

“…However, the oxygen atom of the sildiphenyl ether unit complicated signal assignment, as it could not be detected. The reference compounds diphenyl ether and a poly-mphenyl ether (OS-138) resonated at 117 and 119 ppm, which corresponds roughly to values from the literature ranging from 102 to 114 ppm [21][22][23]. However, the linewidth increased with molecular weight: diphenyl ether (molecular weight 170) exhibits a linewidth of 330 Hz, whereas the poly-m-phenyl ether (molecular weight 554) has a linewidth of above 870 Hz.…”

Structural elucidation of nitro‐substituted five‐membered aromatic heterocycles utilizing GIAO DFT calculations

“…The experimental chemical shifts of C3-Br in 9-12 were predicted poorly using all the basis sets at the B3LYP DFT level. Calculation of carbon chemical shift values when connected to heavy atoms (e.g., Cl) gave a large discrepancy using all the basis sets at the B3LYP DFT level of theory compared to calculations using the Hartree-Fock HF/6-31G (d,p) 27 and SOS-DEPT (density-functional perturbation theory) with IGLO (individual gauges for localized orbital) 28 methods. Therefore, a new computational method is needed to predict the chemical shift values of C-X (X D Cl, Br) using the B3LYP level of theory with a satisfactory correlation to experimental values.…”

A Novel Chlorinated Diphenyl Ether fromByrsonima microphylla(Malpighiaceae)

“…Some predicted 13 C-NMR peaks were attributed through models from the literature 4,5) and by chemical shift calculations obtained by a comparison with experimental halogenated diphenyl ether values. 6) The HSQC and HMBC spectra of this compound permitted the accurate attribution of the carbon peaks and made it possible to propose the partial structures of 1. Thus, the respective correlations ( Fig.…”