Site-selective halogenation of mixed-valent vanadium oxide clusters

Area of Science:

• Inorganic Chemistry
• Materials Science
• Solid-State Chemistry

Background:

• Polyoxovanadate-alkoxide (POV-alkoxide) clusters are versatile inorganic materials.
• Understanding halide defects in metal oxides like VO2 is crucial for electronic applications.
• Previous work established synthesis of a mono-anionic chloride-functionalized cluster.

Purpose of the Study:

• To expand the synthesis and characterization of chloride-functionalized POV-alkoxide clusters.
• To investigate new halogenation routes for mixed-valent vanadium oxide assemblies.
• To explore the electronic consequences of introducing halide defects.

Main Methods:

• Utilized TiCl3(thf)3 and WCl6 as chlorinating agents for vanadium oxide clusters.
• Characterized chloride-containing products using 1H NMR spectroscopy, X-ray crystallography, and elemental analysis.
• Performed electronic analysis via infrared and electronic absorption spectroscopies.

Main Results:

• Developed new synthetic routes for chloride-substituted oxidized Lindqvist vanadium-oxide clusters.
• Successfully synthesized chloride-containing POV-alkoxide clusters [V6O6Cl(OC2H5)12]n (n = 0, 1+).
• Electronic analysis showed redox events localized to the vanadyl portion, with the VIII-Cl moiety remaining reduced over a 1.9 V window.

Conclusions:

• Established novel synthetic pathways for chloride-doped POV-alkoxide clusters from mixed-valent precursors.
• Demonstrated the stability of the chloride defect site under reductive conditions.
• Provided insights into the electronic behavior of halide-defective vanadium oxide materials.