Crystal structure of bis-(μ(2)-meth-anolato-κO:κO)hexa-methyl-bis-(μ(2)-tri-phenyl-acetato-κO:κO')bis-(μ(2)-tri-phenyl-acetato-κ(2) O,O':κO)dialuminiumdi-lanthanum toluene tetra-solvate.

The title compound, [Al(2)La(2)(C(20)H(15)O(2))(4)(CH(3))(6)(CH(3)O)(2)]·4CH(3)C(6)H(5) or [{La(Ph(3)CCOO)(2)(Me(3)AlOMe)}(2)]·4CH(3)C(6)H(5), was formed in a reaction between lanthanum tris-(tetra-methyl-aluminate) and tri-phenyl-acetic acid (1:1) with unintended partial oxidation. The tri-phenyl-acetate ligand exhibits μ(2)-κ(1) O:κ(1) O' bridging and μ(2)-κ(2) O,O':κ(1) O semi-bridging coordination modes, forming a dimeric La(2)(μ-OCO)(4) core. The semi-bridging tri-phenyl-acetate group provides additional bonding with an La(3+) cation via the π-system of one of its phenyl rings. The tri-methyl-meth-oxy-aluminate anion, which is coordinated to the La(3+) cation by its O atom, displays a rather long La-C(Me) bond. Two toluene mol-ecules are each disordered over two orientations about centres of symmetry with site occupancy factors of 0.5. The title compound represents the first example of an Ln(III) complex containing both alkyl alkoxide aluminate and π-bounded arene fragments.