Structures of lanthanide complexes of β-ketophosphoryl compounds

Abstract

Complexes of lanthanide nitrates and prechlorates with the β-ketophosphoryl ligands Ph₂P(O)CH₂C(O)Ph (pdppo) and (BuO)₂P(O)CH₂C(O)Ph (dbpp) have been synthesised and studied by X-ray crystallography, and infrared and NMR spectroscopies. The structures of the lanthanide nitrate complexes with pdppo were found to change in the solid state between the lighter and heavier lanthanides, but form an isostructural series in solution. The X-ray structure of [Er(NO₃)₃(pdppo)₂(OH₂)](R′= 0.031 for 6898 diffractometer observed reflections) shows the metal to be nine-co-ordinated in a distorted tricapped trigonal prism. Both H atoms of the co-ordinated water molecule are involved in hydrogen bonding, one to the carbonyl oxygen of the ligand, and the other to an oxygen atom of a nitrate group of an adjacent molecule. Perchlorate complexes of pdppo have the same composition for the solid complexes but show small structural changes in solution. The complexes of dbpp are all oils. The nitrates appear to be twelve-co-ordinate and isostructural in solution. The perchlorate complexes of dbpp appear to exist as two distinct isostructural classes in solution.