Electronic Structure of Superoxidized Radical Cationic Dodecaborate-Based Clusters

Area of Science:

• Inorganic Chemistry
• Materials Science
• Computational Chemistry

Background:

• Boron clusters exhibit diverse structures and unique bonding, attracting significant theoretical interest.
• Perfunctionalized boron clusters, such as B12(OR)12, are key subjects in cluster chemistry research.
• Understanding redox properties is crucial for exploring new functionalities of boron clusters.

Purpose of the Study:

• To investigate the generality of a newly discovered reversible redox event in perfunctionalized B12(OR)12 clusters.
• To characterize the superoxidized radical cationic form, [B12(OR)12]•+.
• To elucidate the electronic and structural changes associated with the redox process.

Main Methods:

• Comprehensive theoretical studies using (Time-Dependent) Density Functional Theory ((TD-)DFT).
• Electrochemical experiments to probe redox potentials and stability.
• Analysis of spin density distribution and partial charges.

Main Results:

• The reversible redox behavior and the isolation of the [B12(OR)12]•+ species were confirmed for various perfunctionalized B12(OR)12 clusters.
• Spin density in the radical cations is delocalized in the boron core, while supporting groups gain positive partial charges.
• Oxidation potentials are tunable by modifying the electronic properties of the supporting R groups.

Conclusions:

• The identified redox event is general across perfunctionalized B12(OR)12 clusters, offering a pathway for tuning their electrochemical properties.
• The [B12(OR)12]•+ species exhibit characteristic absorption spectra due to mixed local/charge-transfer excitations.
• This work expands the understanding of boron cluster chemistry and their potential applications in redox-active materials.