Polyimido sulfur anions and ylides.

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Classic sulfur-oxygen (SO) molecules are isovalently replaced by NR imido groups to form polyimido sulfur species S(NR)n(m-).
• Access to sulfur diimides S(NR)2 and triimides S(NR)3 is crucial for sulfur-nitrogen (SN) chemistry.
• Previous syntheses of sulfur triimides were hazardous and low-yielding.

Purpose of the Study:

• To develop a facile, safe, and high-yielding route for synthesizing sulfur triimides.
• To explore the coordination chemistry and applications of novel sulfur-nitrogen species and their metal complexes.
• To investigate the electronic structure and bonding in sulfur-nitrogen compounds.

Main Methods:

• Synthesis of triimido sulfites S(NR)3(2-) as precursors.
• Coordination of lithium to triimido sulfites to form inverse tripod ligands.
• Reaction of sulfur diimides and triimides with organometallics to form diimidosulfinates and triimidosulfonates.
• Modification of S-organo substituents to create hemilabile scorpionates.
• Deprotonation of S-alkyl groups to form sulfur-nitrogen ylides.
• Theoretical and experimental charge density investigations, including multipole refinement and topological analyses.

Main Results:

• A new, facile, safe, and quantitative method for synthesizing sulfur triimides via triimido sulfites is presented.
• Triimido sulfites act as rare dianionic tripodal ligands, forming diverse metal complexes.
• Lithium coordination yields inverse tripod ligands capable of anion solvation, stabilizing unprecedented organolithium species.
• Diimidosulfinates and triimidosulfonates exhibit rich coordination chemistry.
• Modified S-organo substituents lead to hemilabile scorpionates with applications in metal coordination and anion solvation.
• Sulfur-nitrogen ylides, isoelectronic to imido groups, show unique coordination behavior.
• Charge density studies rule out hypervalency at sulfur and S=N(C) double bonding as concepts.

Conclusions:

• The developed synthetic route significantly advances the accessibility of sulfur triimides and related SN compounds.
• The novel sulfur-nitrogen species offer versatile platforms for coordination chemistry, catalysis, and anion binding.
• Electronic structure analyses provide fundamental insights into bonding in hypervalent sulfur compounds, refuting traditional bonding models.