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. The conversion reaches 50 % after 14 days and is complete after approximately 20 days. The rate of this {V Sb }→{V Sb } cluster transformation is significantly increased in the presence of ammonium acetate. Applying the new compound as a synthon in the presence of 1,10-phenanthroline (phen) led to crystallization of {Zn(phen) } [Zn(en) V Sb O (H O)]⋅23 H O after a short reaction time, whereas addition of Sb O led to fast crystallization of {(Zn(en) (H O) )(Zn(en) )}[Zn(en) V Sb O (H O)] ⋅8.5 H O. In the crystal structure of {Zn(en) } [V Sb O (H O)]⋅3 en⋅10 H O, the en molecules are seen to be attached to the cluster anion through Sb-N bonds. In the structures of the two new compounds obtained, the [V Sb O (H O)] anions are expanded by Zn -centered complexes through Zn-O-V bond formation.