Self-assembly of a tetrahedral 58-nuclear barium vanadium oxide cluster

Abstract

We report the synthesis and characterization of a molecular barium vanadium oxide cluster featuring high nuclearity and high symmetry. The tetrameric, 2.3 nm cluster H₅[Ba₁₀(NMP)₁₄(H₂O)₈[V₁₂O₃₃]₄Br] is based on a bromide-centred, octahedral barium scaffold which is capped by four previously unknown [V₁₂O₃₃]⁶⁻ clusters in a tetrahedral fashion. The compound represents the largest polyoxovanadate-based heterometallic cluster known to date. The cluster is formed in organic solution and it is suggested that the bulky N-methyl-2-pyrrolidone (NMP) solvent ligands allow the isolation of this giant molecule and prevent further condensation to a solid-state metal oxide. The cluster is fully characterized using single-crystal XRD, elemental analysis, ESI mass spectrometry and other spectroscopic techniques.