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

• A spherical polyoxovanadate was synthesized by stepwise synthesis.
• Host molecules were formed by a template switching reaction from cationic- to anionic-template.
• Spherical tetradecavanadates have a similar structure with dodecavanadates.
• Disk-, to bowl- to ball-type structural conversion was exhibited to incorporate an anion inside the spherical structure.
• A synthetic path that enables the encapsulation of an anion was achieved for spherical oxide molecule.

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.

A bowl-shaped polyoxovanadate, [V12O32(Cl)]5−, was transformed to a spherical polyoxovanadate, [V14O38(Cl)]7− with all of the vanadium atoms in the V(V) oxidation state. The chloride guest was completely enclosed within the spherical cage by a bowl- to ball-type structural conversion.Figure optionsDownload as PowerPoint slide