S₂ N₃⁺ : An Aromatic SN Cation with an N₃ Unit

Area of Science:

• Inorganic Chemistry
• Materials Science
• Theoretical Chemistry

Background:

• Aromaticity in inorganic systems is less explored than in organic chemistry.
• Stable, isolable cations with unique electronic structures are valuable for fundamental studies.
• The S₂N₃⁺ cation presents a novel target for investigating inorganic aromaticity.

Purpose of the Study:

• To synthesize and characterize the S₂N₃⁺ cation.
• To investigate the aromaticity and stability of this novel inorganic cation.
• To elucidate the electronic structure and bonding through experimental and theoretical methods.

Main Methods:

• Single-crystal X-ray diffraction for structural determination.
• Raman and infrared spectroscopy for unequivocal identification.
• Molecular Orbital (MO) and Atoms-in-Molecules (AIM) analyses for electronic structure.

Main Results:

• The first binary six π electron aromatic S₂N₃⁺ cation was successfully synthesized and isolated macroscopically.
• Experimental structural data from X-ray diffraction showed excellent agreement with theoretical predictions.
• Spectroscopic studies (Raman and IR) confirmed the cation's identity.

Conclusions:

• The S₂N₃⁺ cation represents a rare example of a stable, isolable inorganic aromatic system.
• Its stability is attributed to its six π electron aromatic system and the presence of a large counter anion.
• Detailed electronic structure analysis provides insights into bonding in novel inorganic cations.