Sparkle model for the quantum chemical AM1 calculation of europium complexes of coordination number nine

Recently, we have proposed the representation of lanthanides within AM1 as sparkles for the purpose of obtaining ground state geometries of their complexes. In the present work we tested our quantum chemical sparkle model for the prediction of the crystallographic structure of tris (dipivaloylmethanato) (2,2′:6′,2′'-terpyridine) of europium(III), a complex with coordination number nine. Considering the coordination polyhedron, the interatomic distances averaging 2.83 Å and the bond angles could be predicted with an average deviation of 0.12 Å and 5° respectively. This finding reinforces our model and consequently the notion that the lanthanide-ligand interaction is essentially electrostatic.