Redox mediated dimerisation of a cyclo-As₈ complex

Area of Science:

• Inorganic Chemistry
• Materials Science
• Organometallic Chemistry

Background:

• Cyclo-arsenic clusters represent a unique class of main group element compounds.
• Tantalum-based organometallic complexes offer versatile platforms for exploring novel arsenic frameworks.
• Understanding the reactivity and assembly of polyarsenides is crucial for developing new materials.

Purpose of the Study:

• To investigate the redox behavior of the cyclo-As₈ complex [{Cp''Ta}₂(μ,η^2:2:2:2:1:1-As₈)].
• To achieve controlled dimerization and formation of larger arsenic species.
• To characterize the resulting polyarsenide structures and their solution behavior.

Main Methods:

• Electrochemical reduction and oxidation of the [{Cp''Ta}₂(μ,η^2:2:2:2:1:1-As₈)] complex.
• Isolation and characterization of the As₁₆ dicationic species using spectroscopic and crystallographic techniques.
• Solution studies to investigate the disproportionation of the As₁₆ species.

Main Results:

• Controlled dimerization of the cyclo-As₈ complex was achieved through redox manipulation.
• Unprecedented As₁₆ species were synthesized and characterized.
• The As₁₆ dication was found to slowly disproportionate in solution.
• The disproportionation yielded the largest polyarsenide species reported to date in a molecular complex.

Conclusions:

• Redox-driven dimerization provides a viable route to construct complex polyarsenide architectures.
• The observed disproportionation highlights the dynamic nature of large polyarsenide clusters in solution.
• This work expands the scope of known molecular polyarsenides and provides insights into their stability and reactivity.