Heptamethylindenyl lanthanide(III) complexes of lanthanum, neodymium, and erbium

Both the steric bulk and the electronic character of this ligand resulting from the seven methyl groups favor the stabilization of the lanthanide-carbon bonds. Alkali metal salts of heptamethylindenide(Hmi) were used as precursors of the lanthanide complexes. Lanthanum, erbium or neodymium chlorides were added to a stoichiometric amount of potassium Hmi, allowing the mixture to stand at 25/sup 0/C ca 2 days. The product was crystallized and purified by slowly evaporating the remaining THF solution. Solid impurities had already been removed by centrifugation. Complexes were all soluble in THF, benzene, cyclohexane, and unstable in carbon disulfide, alcohols, ketones, DMSO. Each complex was distinguished from the starting material by NMR, and was characterized by ir, uv and visible spectroscopy. 1 table.