An oxygen-passivated vanadium cluster [V@V10O15]− with metal–metal coordination produced by reacting Vn− with O2.

Vanadium cluster anions are highly reactive making the preparation of pure V_n⁻ and the observation of their reactivity extremely challenging. Herein, well-resolved anionic V_n⁻ clusters are prepared enabling an in-depth study on their reactions with O₂ in the gas phase. While pure metal clusters of a magic number are not identified due to the strong V–O bonding, interestingly an unexpected oxide V₁₁O₁₅⁻ was experimentally observed in surviving O₂ etching reactions. First-principles theory calculations indicate that V₁₁O₁₅⁻ possesses a body-centered pentagonal prism structure (D_5h,), with the V@V₁₀ core fully protected by 15 oxygen bridges. Such an oxygen-protected metal cluster [V@V₁₀O₁₅]⁻ exhibits typical superatom orbital features pertaining to the V@V₁₀ core which shows effective metal–metal coordination bonding. Meanwhile, the high stability of [V@V₁₀O₁₅]⁻ is reinforced by the V–O–V conjugation interactions which help to maintain the structural integrity, resulting in 3D inorganic aromaticity. This finding of such an oxygen-passivated superatom cluster sheds light on the bonding nature in ligand-protected metal clusters via wet synthesis. [ABSTRACT FROM AUTHOR]