Abstract: | The syntheses of Hg(X)OAc] (OAc=acetate; X=CN, Cl, Br, I, SCN) are reported, and the crystal structure of the cyano complex has been determined. The asymmetric unit contains two Hg(CN)OAc] molecules which show almost linear C–Hg–O bonding (Hg–C=2.019(13), 2.016(11) Å; Hg–O=2.067(9), 2.058(8) Å; C–Hg–O=176.0(4), 172.3(5)°), with only one of the two acetate oxygen atoms bound directly to the mercury atom. Secondary HgO and HgN contacts in the range 2.6–2.8 Å are about 0.2 Å shorter than the secondary HgO contacts in the corresponding X=Ph complex. The ν(HgX) and ν(HgO) modes have been assigned in the IR and Raman spectra of Hg(X)OAc] (X=CN, Cl, Br, I, SCN); these spectra show that the complexes have structures with essentially linear O–Hg–X bonding, similar to that of the cyanide. Solid-state 199Hg MAS NMR spectra have been recorded for HgX2 (X=CN, Cl) and Hg(X)OAc] (X=Me, Ph, CN, Cl, SCN), and spinning sideband analysis has been used to determine the 199Hg shielding anisotropy and asymmetry parameters Δσ and η. A semi-empirical method for the calculation of the local paramagnetic contribution to the shielding is given, and a linear relationship between Δσ and the isotropic shielding σiso which is predicted by this model for linear HgXY species is found to be obeyed reasonably well by the experimental data for HgX2 and Hg(X)OAc]. The same method is used to analyse the effects of secondary bonding on the 199Hg shielding parameters. The 13C MAS NMR spectrum of Hg(SCN)OAc] shows 2J(199Hg13C) and 3J(199Hg13C) coupling to the acetate carbon atoms, with magnitudes similar to those found previously for Hg(OAc)2. The CN carbon signals in Hg(CN)2 and Hg(CN)OAc] are split into 2:1 doublets due to residual dipolar coupling to the quadrupolar 14N nucleus. |