Mercury(I) complexes with bidentate iminopyridine ligands: Synthesis, spectral characterization and structural analysis

Four mercury(I) complexes, [(LHgHgL2)-Hg-2](NO3)(2) (L-2 = (4-fluorophenyl)pyridin-2-ylmethyleneamine, 1; (4-dichlorophenyl)pyridin-2-ylmethyleneamine, 2; (4-bromophenyl)pyridin-2-ylmethyleneamine, 3 and (4-iodophenyl)pyridin-2-ylmethyleneamine, 4) have been synthesized and characterized by CHN analysis, IR and UV-Vis spectroscopy. The crystal structures of 1 and 3 were determined by single crystal X-ray spectroscopy. These complexes contain the Hg-2(2+) moiety with a mercury-mercury bonded core, in which one diimine ligand is coordinated to each mercury atom. The Hg atoms have an additional axial interaction with the oxygen atom of the NO3- anion in both complexes. Complex 1 shows a step in the Hg-Hg bond due to the parallel configuration of the planar ligands. However, the ligand planes in the complex 3 are nearly planar and these planes are approximately perpendicular to each other. Supramolecular structures were built in both complexes via pi-pi stacking of the diimine ligands. (C) 2009 Elsevier Ltd. All rights reserved.