Ligated aluminum cluster anions, LAln− (n = 1–14, L = N[Si(Me)3]2)

Abstract

A wide range of low oxidation state aluminum-containing cluster anions, LAl_n⁻ (n = 1–14, L = N[Si(Me)₃]₂), were produced via reactions between aluminum cluster anions and hexamethyldisilazane (HMDS). These clusters were identified by mass spectrometry, with a few of them (n = 4, 6, and 7) further characterized by a synergy of anion photoelectron spectroscopy and density functional theory (DFT) based calculations. As compared to a previously reported method which reacts anionic aluminum hydrides with ligands, the direct reactions between aluminum cluster anions and ligands promise a more general synthetic scheme for preparing low oxidation state, ligated aluminum clusters over a large size range. Computations revealed structures in which a methyl-group of the ligand migrated onto the surface of the metal cluster, thereby resulting in “two metal-atom” insertion between Si–CH₃ bond.