A Homoleptic Ga ₄ Radical Anion: Isolation, Characterization, and Reactivity

Abstract

ABSTRACT We report the synthesis and characterization of a homoleptic Ga 4 radical anion ([Li + ]•[ 1 •− ]), prepared via a salt‐metathesis reaction between Cp*Ga (Cp* = pentamethylcyclopentadienyl) and [Li 2 (L)] (L = Me 2 Si(DipN) 2 ). Combined structural and computational analyses reveal a nearly planar geometry at the central gallium atom, with only minimal distortion toward a trigonal pyramidal geometry, and the unpaired spin density localized in its 4p orbital. Density functional theory (DFT) calculations elucidate the reaction mechanism for the formation of [Li + ]•[ 1 •− ], while N ‐heterocyclic carbene (NHC)‐trapping experiments led to the isolation of NHC‐stabilized digallyl digallenes ( 2a and 2b ) as well as a digallyl‐substituted gallium radical ( 3c ). Compound [Li + ]•[ 1 •− ] exhibits versatile gallium‐centered radical reactivity, including one‐electron oxidation with S 8 and facile E─E bond activation (E = S, Se, and I) toward PhS‐SPh, PhSe‐SePh, and I 2 .