Crystal structures of three mercury(II) complexes [HgCl2 L] where L is a bidentate chiral imine ligand

The crystal structures of three complexes [HgCl2 L] were determined, namely, (S)-(+)-di-chlorido-[1-phenyl-N-(pyridin-2-yl-methyl-idene)ethyl-amine-κ(2) N,N']mercury(II), [HgCl2(C14H14N2)], (S)-(+)-di-chlorido-[1-(4-methyl-phen-yl)-N-(pyridin-2-yl-methyl-idene)ethyl-amine-κ(2) N,N']mercury(II), [HgCl2(C15H16N2)], and (1S,2S,3S,5R)-(+)-di-chlorido-[N-(pyridin-2-yl-methyl-idene)isopino-camph-eyl-amine-κ(2) N,N']mercury(II), [HgCl2(C16H22N2)]. The complexes consist of a bidentate chiral imine ligand coordinating to HgCl2 and crystallize with four independent mol-ecules in the first complex and two independent mol-ecules in the other two. The coordination geometry of mercury is tetra-hedral, with strong distortion towards a disphenoidal geometry, as a consequence of the imine bite angle being close to 70°. The Cl-Hg-Cl angles span a large range, 116.0 (2)-138.3 (3)°, which is related to the aggregation state in the crystals. For small Cl-Hg-Cl angles, complexes have a tendency to form dimers, via inter-molecular Hg⋯Cl contacts. These contacts become less significant in the third complex, which features the largest intra-molecular Cl-Hg-Cl angles.