A Bowl-Type Dodecavanadate as a Halide Receptor.

Area of Science:

• Inorganic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Dodecavanadate frameworks, [V12O32]4-, possess a unique bowl-type structure with an accessible molecular oxide cage.
• Previous synthetic strategies required specific pathways for incorporating different guests into the cage.
• Understanding guest inclusion and its effect on cage structure is crucial for developing functional materials.

Purpose of the Study:

• To synthesize a new dodecavanadate compound with a nitromethane guest and investigate its guest-capturing capabilities.
• To explore the use of this nitromethane-containing dodecavanadate as a precursor for halide-centered analogues.
• To correlate the size of halide guests with their position and inclusion rates within the dodecavanadate cage.

Main Methods:

• Synthesis of a novel dodecavanadate compound {(n-C4H9)4N}4[V12O32(CH3NO2)] (1) via a new synthetic route.
• Characterization of halide-centered dodecavanadates {(C2H5)4N}5[V12O32(X)] (X = Cl-, Br-, I-) derived from compound 1.
• Utilized 51V NMR time-course measurements in nitromethane to study inclusion reaction kinetics.

Main Results:

• A new dodecavanadate, compound 1, was synthesized with nitromethane guest partially occupying the cage, enabling guest-capture reactions.
• Compound 1 successfully served as a precursor for halide-centered dodecavanadates (2-4).
• The position of halide ions (Cl-, Br-, I-) within the cage correlated with their ionic radii, and inclusion rates increased in the order I- < Br- < Cl-.

Conclusions:

• The synthesized dodecavanadate framework demonstrates tunable guest inclusion properties based on guest size and type.
• The nitromethane-containing dodecavanadate is a versatile precursor for generating various functionalized cage compounds.
• This study provides insights into the structure-property relationships of molecular oxide cages and their potential applications.