199Hg Shielding Tensor in Methylmercury Halides: NMR Experiments and ZORA DFT Calculations

Abstract

The isotropic average, , and the anisotropy, ΔσHg, of the 199Hg shielding tensor in methylmercury halides, CH3HgX (X = Cl, Br, I), were determined by studying the 199Hg NMR of these molecules dissolved in liquid crystals. Furthermore, density functional calculations were performed using the zeroth order regular approximation, inluding also dimethylmercury. Detailed comparison of the experimental and calculated results is problematic because of the sensitivity of the 199Hg shielding to environmental effects. It is, however, clear that calculations with spin−orbit interaction taken into account lead to the and ΔσHg values that predict the same trend as the experiments; the chemical shift relative to dimethylmercury, ((CH3)2Hg) − (CH3HgX), increases while the shielding anisotropy decreases along the series (CH3)2Hg to CH3HgI.