Aluminum Alkali Metalate Derivatives: Factors Driving the Final Nuclearity in the Crystal Form

In this paper, we have completed the synthesis and characterization of a family of aluminum alkali metalate derivatives [MAlMe4–x{2,6‐(MeO)2C6H3O}x]n (x = 1, 2; M = Li, Na, K) by preparing the new heterometallic ‐ate compounds [MAlMe3{2,6‐(MeO)2C6H3O}]2 (M = Na and K) through the reaction between [AlMe3]2 and the appropriate alkali metal aryloxide [M{2,6‐(MeO)2C6H3O}]n (M = Na and K). Surprisingly, the solid‐state structures for these species, determined by X‐ray diffraction, show a different nuclearity than the lithium one, [AlLiMe3{2,6‐(MeO)2C6H3O}]3 previously reported by us. This behavior contrasts to the one observed when [Al(OR)Me2] is used as the aluminum precursor, which gives the tetrametallic species [AlMMe2{2,6‐(MeO)2C6H3O}2]2. To rationalize the origins of the final nuclearity variation in the solid state within this family of heterometallic ‐ate compounds, a DFT study has been performed. The results of this analysis on whether the nuclearity in the solid state could stem from crystallization factors or from how the chemical attack had taken place are presented. Reaction of [M(OR)]6 (M = Li, Na, K) with different aluminum precursors leads to aluminates with an Al2M2 or Al3M3 core. To rationalize the driving forces directing the final nuclearity, DFT calculations have been performed.