Isolation of a Nitromethane Anion in the Calix-Shaped Inorganic Cage.

A calix-shaped polyoxometalate, [VO] (), stabilizes an anion moiety in its central cavity. This molecule-sized container has the potential to control the reactivity of an anion. The highly-reactive cyanate is smoothly trapped by to form [VO(CN)].

Synthesis and structural characterization of tube-type tetradecavanadates.

By the reaction of ammonium perchlorate with anion-incorporated bowl-type dodecavanadates, viz. [VO(X)] [X = N (1), OCN and NO], tube-type tetradecavanadates, viz. (NH)[VO(X)] [X = N (2), OCN (3) and NO (4)] were synthesized.

Solid-State Umbrella-type Inversion of a VO 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 O ] (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.

Small-Molecule Anion Recognition by a Shape-Responsive Bowl-Type Dodecavanadate.

A dodecavanadate, [V O ] , is an inorganic bowl-type host with a cavity entrance with a diameter of 4.4 Å in the optimized structure. Linear, bent, and trigonal planar anions are tested as guest anions and the formation of host-guest complexes, [V O (X)] (X=CN , OCN , NO , NO , HCO , and CH CO ), were confirmed by X-ray crystallographic analyses and a V NMR spectroscopy study.

A Bowl-Type Dodecavanadate as a Halide Receptor.

The dodecavanadate framework, [VO], exhibits a unique bowl-type structure with an open molecular oxide cage having a cavity diameter of 4.4 Å, and different synthetic paths were required to construct the bowl-type structure with a different guest. A new dodecavanadate, {(-CH)N}[VO(CHNO)] (), is synthesized with a nitromethane guest, which is stacked above the entrance of the hemisphere rather than fully occupying the cavity, and it enables a guest-capturing reaction, while retaining the anionic cage structure.

A chloride capturing system via proton-induced structure transformation between opened- and closed-forms of dodecavanadates.

Chloride-incorporated dodecavanadates show two distinct structures of the monoprotonated-form [HV12O32(Cl)](4-) (closed-V12) with a spherical closed-structure and the opened-form [V12O32(Cl)](5-) (opened-V12). The reaction of closed-V12 with a stoichiometric amount of ethylenediamine drives the structure transformation reaction to opened-V12, quantitatively. From time dependent observations of (51)V NMR, a tube-type intermediate [V12O32(Cl)](5-) (tube-V12) was observed in the transformation process.