Crystal structure of lead(ii) acetylacetonate and the structure of the acetylacetone solvated lead(ii) ion in solution studied by large-angle X-ray scattering

Abstract

The crystal structure of bis(acetylacetonato)lead(II) and the structure of the acetylacetone solvated lead(II) ion in solution have been determined by single-crystal X-ray diffraction and large-angle X-ray scattering (LAXS), respectively. The acetylacetone is deprotonated and acts as a bidentate anionic ligand (acac⁻) in the solid Pb(acac)₂ compound. The lead(II) ion binds four oxygen atoms strongly in a nearly flat pyramidal configuration with Pb–O bond lengths in the range 2.32–2.37 Å, and additionally three oxygens from neighboring complexes at 3.01–3.26 Å. Acetylacetone acts as a solvent (Hacac) at dissolution of lead(II) trifluoromethanesulfonate forming a pentasolvate with a mean Pb–O bond distance of 2.724(5) Å. The 6s² lone electron pair on the lead(II) ion becomes stereochemically active in the crystalline acetylacetonate complex, while it is inactive in the solvate in solution. The solution was also analysed using IR and ¹H NMR spectroscopy.