Preparation and X-ray crystal structures of Li-4[Hg-2(edta)(2)]center dot 8H(2)O and Ba-2[Hg-2(teta)(2)]center dot 9H(2)O (teta = N,N,N ',N '-diaminobutanetetraacetate)

The Hg(II) complexes of the N,N,N',N'-tetraacetate of 1,2-diaminoethane (edta) and 1,4-diaminobutane (teta) were crystallized from concentrated aqueous solutions. The first ligand gave crystals of Li-4[Hg-2(edta)(2)]. 8H(2)O. Its single crystal X-ray structure determination (triclinic space group P (1) over bar with a = 9.369(3), b = 9.354(3), c = 11.584(4) Angstrom, alpha = 67.90(2), beta = 67.50(2), gamma = 80.42(3)degrees and Z = 1) showed that each mercury(II) is mainly bound to six donor atoms of the same ligand anion. The coordinated anionic ligand is strained and leaves sufficient space for a seventh donor atom, i.e. a coordinated oxygen atom of the nearest complex ion bound with a much shorter Hg-O distance. The second ligand gave Ba-2[Hg-2(teta)(2)]. 9H(2)O (space group C2/c with a = 17.840(2), b = 15.243(2), c = 18.962(6), beta = 113.84(1)degrees and Z = 4) containing two equivalent ligand anions giving the simplest polymeric structure, i.e. a dimer. These results are in agreement with the data obtained from equilibrium studies.