Crystal structure of bis(μ2-methanolato-κO:κO)hexamethylbis(μ2-triphenylacetato-κO:κO′)bis(μ2-triphenylacetato-κ2 O,O′:κO)dialuminiumdilanthanum toluene tetrasolvate

The title compound, [Al₂La₂(C₂₀H₁₅O₂)₄(CH₃)₆(CH₃O)₂]·4CH₃C₆H₅ or [{La(Ph₃CCOO)₂(Me₃AlOMe)}₂]·4CH₃C₆H₅, was formed in a reaction between lanthanum tris(tetramethylaluminate) and triphenylacetic acid (1:1) with unintended partial oxidation. The triphenylacetate 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 triphenylacetate group provides additional bonding with an La³⁺ cation via the π-system of one of its phenyl rings. The trimethylmethoxyaluminate anion, which is coordinated to the La³⁺ cation by its O atom, displays a rather long La—C_Me bond. Two toluene molecules 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.