Diverse Reactivity of a Pincer-Type Dialuminum Complex

Abstract

Although the main group complexes supported by trianionic pincer-type ligands have attracted significant attention, the chemistry of aluminum remains underdeveloped. Herein, we report the diverse reactivity of a trimethyl dialuminum(III) complex (1) supported by a trianionic [NNN]^3– pincer ligand. Treatment of 1 with tetrahydrofuran and protic substrates (2,6-diisopropylphenol, 2,6-diisopropylaniline, and borane ammonia complex) leads to a series of cyclic dialuminum species (2–5), characterized by nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography. Key transformations include solvent-induced structural rearrangement (2) and protonolysis of bridging Al–CH₃ bonds (3–5). Additionally, iodination of the terminal methyl groups in 3 and 4 results in the formation of asymmetric 6 and symmetric 7, respectively. Further reactions of iodinated derivative 6 with N-heterocyclic carbene (NHC) and acetonitrile generate spirocyclic (8) and insertion (9) products.