SPARKLE MODEL FOR THE QUANTUM-CHEMICAL AM1 CALCULATION OF EUROPIUM COMPLEXES

Considering that the bonds between a lanthanide and its ligands essentially possess an electrostatic character, we propose the representation of rare-earth elements within AM 1 as sparkles. To parametrize the sparkle model we have used the known geometry of the complex tris (acetylacetonate) (1,10-phenantroline) of europium (III). Interatomic distances for the coordination polyhedron, averaging 2.81 angstrom, could be predicted with an average deviation of 0.13 angstrom. In short, this is a simple lanthanide-ligand electrostatic model which simultaneously treats the organic ligands and their interactions with the powerful AM1 method, yielding results of useful accuracy.