Quantum chemistry investigation of electronic structure and NMR spectral characteristics for fluorides of dialkylamidosulfoxylic acids and related compounds

The parent (H2N-S-F) and N,N-dialkyl-substituted fluorides of amidosulfoxylic acid (R2N-S-F, R=Me or R2N=Morph) as well as the related compounds X-S-F (X=CH3, OH, F, SiH3, PH2, SH, Cl) have been investigated with quantum chemical calculations at the ab initio (MP2) level of approximation. The geometries, electronic structures, molecular orbital (MO) energies and NMR chemical shift values have been calculated to evaluate the role and extent of the polarization and delocalization effects in forming of the high-field fluorine NMR resonances within the series of interest. The delta F magnitudes for all investigated fluorides of amidosulfoxylic acid as well as the delta N value calculated for Me2N-S-F are in the good agreement with the F-19 and N-14 NMR chemical shift values measured experimentally. For the parent compounds, H2N-S-F and H2N-SO2-F, the orientation of principal axes of the magnetic shielding tensors and the corresponding principal sigma(ii) values along these axes have been qualitatively interpreted basing on the analysis of the MO interactions in the presence of the rotating magnetic field. Copyright (C) 2009 John Wiley & Sons, Ltd.