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

The title compound, [Al2 La2 (C20 H15 O2 )4 (CH3 )6 (CH3 O)2 ]·4CH3 C6 H5 or [{La(Ph3 CCOO)2 (Me3 AlOMe)}2 ]·4CH3 C6 H5 , 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 μ2 -κ1 O :κ1 O ' bridging and μ2 -κ2 O , O ':κ1 O semi-bridging coordination modes, forming a dimeric La2 (μ-OCO)4 core. The semi-bridging tri-phenyl-acetate group provides additional bonding with an La3+ cation via the π-system of one of its phenyl rings. The tri-methyl-meth-oxy-aluminate anion, which is coordinated to the La3+ cation by its O atom, displays a rather long La-CMe 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 LnIII complex containing both alkyl alkoxide aluminate and π-bounded arene fragments.