Mercury(II) Complexes Containing the [Hg(L)2]2–, [Hg(L)(HL)]−, and [Hg(HL)2] Units [H2L = 3-(2-Chlorophenyl)-2-sulfanylpropenoic Acid]. Structural and Spectroscopic Effects of the Different Degrees of Ligand Protonation

The reaction of mercury(II) acetate with 3-(2-chlorophenyl)-2-sulfanylpropenoic acid (H2Clpspa) in ethanol in the presence (or absence) of diisopropylamine or triethylamine yielded the compounds [HQ]2[Hg(Clpspa)2] (1), [HP][Hg(Clpspa)(HClpspa)] (2) (where HQ = diisopropylammonium and HP = triethylammonium cations), and [Hg(HClpspa)2] (3). All of the new compounds were characterized by elemental analysis, IR, and NMR (1H, 13C, 199Hg) spectroscopy. The crystal structures of 1, 2, and 3·4H2O were determined by X-ray diffractometry. Diisopropylammonium cations and [Hg(Clpspa)2]2– anions were detected in the first compound, triethylammonium cations and [Hg(Clpspa)(HClpspa)] anions were found in the second compound, and molecular [Hg(HClpspa)2] units were found in the third. The different degrees of ligand protonation modify the structural parameters of the Hg-kernel as well as the supramolecular association in the compounds. Furthermore, the spectroscopic characteristics of the compounds in the solid (IR) and in solution (NMR) are sensitive to this ligand protonation.