Synthetic Motifs for Understanding Lewis Acid Interactions with Persulfides and Thioselenides

Area of Science:

• Bioinorganic Chemistry
• Organometallic Chemistry
• Coordination Chemistry

Background:

• Persulfides (RSS⁻) and thioselenides (RSSe⁻) are crucial in biological sulfur and selenium transfer reactions.
• Lewis acidic moieties modulate the reactivity of these chalcogen species.
• Understanding metal interactions with persulfides and thioselenides is key to biological processes.

Purpose of the Study:

• To synthesize and characterize mononuclear zinc persulfide and thioselenide complexes.
• To investigate the impact of Lewis acid coordination on thioselenide electronic structure and reactivity.
• To compare the nucleophilicity of zinc-bound persulfides with parent thiolates.

Main Methods:

• Synthesis of mononuclear Zn²⁺ persulfide and thioselenide complexes using dichalcogenide precursors.
• Characterization using ⁷⁷Se NMR spectroscopy to probe electronic environments.
• Reactivity studies involving nucleophilic attack and alkylation reactions.

Main Results:

• Coordination of thioselenides to Zn²⁺ polarizes the Se-S bond, facilitating selenide release.
• Zinc-bound persulfides exhibit enhanced nucleophilicity compared to thiolates, attributed to the α-effect.
• Demonstrated differences in reactivity between persulfide and thiolate complexes.

Conclusions:

• Mononuclear zinc complexes serve as valuable synthetic models for studying biological sulfur and selenium chemistry.
• Metal coordination significantly alters the reactivity of persulfides and thioselenides.
• The findings provide new insights into metal-chalcogenide interactions and biological transfer reactions.