On the solvation of the mercury(I) ion. A structural, vibration spectroscopic and quantum chemical study

The structure of the solvated mercury(I) ion in solvents such as water, methanol, dimethylsulfoxide, N,N′-dimethylpropyleneurea, acetonitrile and pyridine solution has been studied by means of EXAFS and/or large angle X-ray scattering (LAXS). Raman spectroscopy has been used for the determination of the Hg–Hg stretching frequencies. The Hg–Hg bond length increases with increasing solvating ability of the solvent, while the stretching frequency appears to be almost invariant. The results of quantum chemical calculations indicate a significant influence on the Hg–Hg bond from solvation. The structure of solid anhydrous mercury(I) trifluoromethanesulfonate, Hg2(CF3SO3)2 (1), has been determined by powder diffraction methods. The structure comprises of discrete molecules, where each mercury binds to an oxygen atom in the anion, forming an almost linear O–Hg–Hg–O entity; the Hg–Hg–O angle is 173° and the Hg–Hg and Hg–O bond lengths are 2.486(6) and 2.099(22) Å, respectively.