Structural conversion from bowl- to ball-type polyoxovanadates: Synthesis of a spherical tetradecavanadate through a chloride-incorporated bowl-type dodecavanadate

A spherical tetradecavanadate, [V14O38(Cl)]7−, was synthesized from a chloride-incorporated bowl-type dodecavanadate, [Cl⊂V12O32]5−, which was prepared through a template switching reaction from [Cu2V8O24]4− using the cation template removal reagent, hydrogen cyanide. X-ray structure analysis revealed a spherical V(V) polyoxovanadate framework, without V(IV) valence state. The two-step process, involving transformation of a disk to a bowl, then transformation from the bowl to a ball, enables the incorporation of a guest anion inside the ball. An alternative route from a hexadecavanadate, which avoids the use of hydrogen cyanide, is also described.