Solid‐State Umbrella‐type Inversion of a VO 5 Square‐Pyramidal Unit in a Bowl‐type Dodecavanadate Induced by Insertion and Elimination of a Guest Molecule

Design of cavities for a target molecule and the elucidation of the corresponding host–guest interactions are important for molecular manipulation. A discrete dodecavanadate bowl, [V 12 O 32 ] 4− ( V12 ), with an entrance diameter of 4.4 Å and an electron‐rich guest at the center of the bowl, was stabilized by electrostatic interactions. A characteristic of V12 is a solid‐state polytopal rearrangement during guest elimination and recapture. A guest‐free dodecavanadate, [V 12 O 32 ] 4− ( V12‐free ), was prepared by removal of the guest from CH 2 Cl 2 ‐inserted V12 under vacuum at 50 °C. Single‐crystal X‐ray analysis revealed that one of the VO 5 square pyramids at the bottom of V12‐free was inverted to fill the void of the bowl cavity. The exposure of V12‐free to the guest molecule vapors of CH 2 Cl 2 , 1,2‐dichloroethane, MeNO 2 , MeCN, and MeBr resulted in the selective insertion of the guest to reform the guest‐inserted V12 structure. Whereas CO 2 could be inserted in the V12 bowl, CH 4 and CO could not.