Oxidative Bond Formation and Reductive Bond Cleavage at Main Group Metal Centers: Reactivity of Five-Valence-Electron MX₂ Radicals

Monomeric five-valence-electron bis­(boryl) complexes of gallium, indium, and thallium undergo oxidative M–C bond formation with 2,3-dimethylbutadiene, in a manner consistent with both the redox properties expected for M^II species and with metal-centered radical character. The weaker nature of the M–C bond for the heavier two elements leads to the observation of reversibility in M–C bond formation (for indium) and to the isolation of products resulting from subsequent B–C reductive elimination (for both indium and thallium).