Aluminylation: a generalizable route towards low-valent aluminum under moderate conditions with controlled product nuclearity through precursor design.

Recent advances in isolating and characterizing reactive aluminylenes and aluminyl anions have redefined the landscape of low-valent aluminum chemistry. Study of these molecules that span a wide range of structures and ligand environments have helped established new paradigms in main-group metal bonding and reactivity; however, their controlled access remains limited by aggregation, disproportionation, and oxidation of reactive Al(i) intermediates. Herein, we establish aluminylation as a generalizable redox-neutral synthetic route to low-valent aluminum complexes. By circumventing the use of external reductants through metathesis reactions between Al(i) precursors and alkali metal ligand salts, we can access novel heteroleptic clusters as well as known aluminyl complexes with improved yields or under more mild conditions. We demonstrate that the equilibrium of the Al(i) precursor between monomeric or oligomeric cyclopentadienyl aluminum species directly governs reaction outcomes and enables selective formation of products across multiple ligand classes.