Tuning the Anomeric Effect in Sulfamide with Superacids.

Area of Science:

• Inorganic Chemistry
• Solid-State Chemistry
• Computational Chemistry

Background:

• The anomeric effect, a form of negative hyperconjugation, influences molecular geometry in compounds with short S-N bonds, such as sulfamide.
• Superacidic media offer unique environments for studying chemical interactions and structural modifications.

Purpose of the Study:

• To investigate the tunability of the anomeric effect in sulfamide using superacidic media.
• To characterize the structural and electronic changes in protonated sulfamide species.
• To correlate experimental findings with quantum chemical calculations.

Main Methods:

• Reaction of sulfamide in binary superacidic systems (XF/MF5 and HF/BF3).
• Characterization of resulting salts using low-temperature vibrational spectroscopy.
• Single crystal X-ray diffraction studies of protonated sulfamide salts.
• Quantum chemical calculations to support experimental observations.

Main Results:

• Formation of colorless sulfamide salts, including [X2 NSO2 NX3 ]+ [MF6 ]- and [H2 NSO2 NH3 ]+ [BF4 ]-.
• Observation of exclusive N,N'-diprotonation in the HF/SbF5 system.
• Detailed structural analysis of protonated sulfamide salts ([H2 NSO2 NH3 ]+ [BF4 ]- and [H3 NSO2 NH3 ]2+ 2[SbF6 ]⋅2HF) via X-ray diffraction.
• Significant changes in sulfur-nitrogen bond lengths upon mono- and diprotonation.

Conclusions:

• Superacidic media effectively tune the anomeric effect in sulfamide.
• Protonation induces substantial structural modifications in sulfamide, particularly affecting S-N bond lengths.
• Experimental and computational data provide a comprehensive understanding of protonated sulfamide structures.