Soluble Hetero-Polyoxovanadates and Their Solution Chemistry Analyzed by Electrospray Ionization Mass Spectrometry.

Polyoxometalates (POMs) are an intriguing class of compounds due to their tremendous structural variety and the wide spectrum of resulting properties, which make them interesting for applications in fields such as catalysis, material science or nanotechnology. Their ability to form large supramolecular architectures by self-assembly offers an entry to complex, functional systems. After an introduction into the structure and synthesis of POMs of the early transition metals, recently discovered water-soluble antimonato polyoxovanadates (Sb-POVs) and the investigation of their chemical reactivity are discussed.

New Water-Soluble Cluster Compound {Zn(en) } [V Sb O (H O)]⋅ (Ethylenediamine) ⋅10 H O as a Synthon for the Generation of Two New Antimonato Polyoxovanadates.

A new antimonato polyoxovanadate {Zn(en) } [V Sb O (H O)]⋅3 en⋅10 H O (en=ethylenediamine) synthesized under hydrothermal conditions exhibits remarkable solubility in water. Electrospray ionization mass spectrometry (ESI-MS) investigations on an aqueous solution demonstrate that the cluster core remains fully intact for 72 h. At longer times, slow transformation into a {V Sb O } cluster is observed.

Configurational Isomerism in Polyoxovanadates.

A water-soluble derivative of the polyoxovanadate {V E O } (E=semimetal) archetype enables the study of cluster shell rearrangements driven by supramolecular interactions. A reaction unique to E=Sb, induced exclusively by ligand metathesis in peripheral [Ni(ethylenediamine) ] counterions, results in the formation of the metastable α * configurational isomer of the {V Sb O } cluster type. Contrary to all other polyoxovanadate shell architectures, this isomer comprises an inward-oriented vanadyl group and is ca.