Magnetic communication and reactivity of a stable homometallic cation–cation trimer of pentavalent uranyl

Abstract

The reaction of the UO₂⁺ precursor [(UO₂Py₅)(KI₂Py₂)]_n, with the potassium salt of the tetradentate aza β-diketiminate ligand L (L = 2-(4-tolyl)-1,3-bis(quinolyl)malondiiminate) affords the first homometallic cation–cation complex of pentavalent uranyl. The complex [UO₂L]₃ has a new triangular geometry of the cation–cation interaction in the solid state, which gives rise to a clear magnetic interaction with a maximum in the plot of χ versus T at 12 K. It retains its solid state trinuclear structure in solution and is fully stable in organic anaerobic solvents, but reacts rapidly with molecular oxygen to form a rare dinuclear oxo complex of uranyl(VI), ([UO₂(L)]₂[μ₂-O]).