Crystal structures of three mercury(II) complexes [HgCl2L] where L is a bidentate chiral imine ligand

Abstract

The crystal structures of three complexes [HgCl2L] were determined, namely, (S)-(+)-dichlorido[1-phenyl-N-(pyridin-2-ylmethylidene)ethylamine-κ2N,N′]mercury(II), [HgCl2(C14H14N2)], (S)-(+)-dichlorido[1-(4-methylphenyl)-N-(pyridin-2-ylmethylidene)ethylamine-κ2N,N′]mercury(II), [HgCl2(C15H16N2)], and (1S,2S,3S,5R)-(+)-dichlorido[N-(pyridin-2-ylmethylidene)isopinocampheylamine-κ2N,N′]mercury(II), [HgCl2(C16H22N2)]. The complexes consist of a bidentate chiral imine ligand coordinating to HgCl2 and crystallize with four independent molecules in the first complex and two independent molecules in the other two. The coordination geometry of mercury is tetrahedral, 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 intermolecular Hg...Cl contacts. These contacts become less significant in the third complex, which features the largest intramolecular Cl—Hg—Cl angles.

Keywords

• crystal structure
• mercury
• Schiff base
• disphenoidal geometry