METAL BETAINE INTERACTIONS .15. MERCURY(II) CHLORIDE ADDUCTS OF BETAINE DERIVATIVES

The structures of the complexes [{Hg2(Me3NCHCO2)2Cl4.2HgCl2}n] 1 [{Hg2(C5H5NCH2CO2)2Cl4. HgCl2}n] 2 and [Hg2(C5H5NCH2CH2CO2)2(mu-Cl)2Cl2] 3 have been determined by X-ray crystallography. That of 1 features a centrosymmetrical bis(carboxylato-O)-bridged dimeric unit with each metal atom co-ordinated by two terminal chloro ligands; the HgCl2 moieties are linked by secondary bonds to the chloro ligands and oxygen atoms of neighbouring dimeric units to form a two-dimensional network. Complex 2 contains an analogous dimeric unit connected by unusual bis(carboxylato-mu-O,O') bridges. Complex 3 comprises discrete dimeric molecules in which each betaine ligand functions in an unsymmetrical bidentate O,O' mode.