Syntheses, X-ray crystal structure, and vibrational spectra of L-cysteinato(methyl)mercury(II) monohydrate

Abstract

The title complex has been prepared from the reaction of L-cysteine with methylmercury hydroxide or chloride in basic solution and characterised by single-crystal X-ray diffractometry. Crystals are orthorhombic, space group P2₁2₁2₁, with unit cell dimensions a= 6·386(6), b= 26·026(13), c= 5·282(4)Å and Z= 4. The structure was solved by Patterson and Fourier techniques and refined by full-matrix least-squares methods to a final R of 0·065 for 980 independent observed reflections measured on an automatic diffractometer. The amino-acid is co-ordinated to Hg via a deprotonated sulphydryl group [Hg–S 2·352(12)Å]. A weak intramolecular Hg ⋯ O interaction [2·85(2)Å] to a carboxylate group is present. Individual molecules of the complex are linked by hydrogen bonds to solvent water molecules. The vibrational spectra of the complex are discussed [ν(Hg–S) 326 cm^–1].