Metal–betaine interactions. Part 15. Mercury(II) chloride adducts of betaine derivatives

Abstract

The structures of the complexes [{Hg₂(Me₃NCH₂CO₂)₂Cl₄·2HgCl₂}_n]1[{Hg₂(C₅H₅NCH₂CO₂)₂Cl₄·HgCl₂}_n]2 and [Hg₂(C₅H₅NCH₂CH₂CO₂)₂(µ-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 net-work. Complex 2 contains an analogous dimeric unit connected by unusual bis(carboxylato-µ-O,O′) bridges. Complex 3 comprises discrete dimeric molecules in which each betaine ligand functions in an unsymmetrical bidentate O,O′ mode.