Short intramolecular S...O interactions in S-substituted 2-mercaptoacetophenones

Area of Science:

• Organic Chemistry
• Crystallography
• Computational Chemistry

Background:

• Intramolecular interactions play a crucial role in determining the structure and properties of organic molecules.
• Sulfur- and oxygen-containing organic compounds exhibit diverse bonding characteristics.
• Previous studies on acetophenone derivatives have explored various structural and electronic aspects.

Purpose of the Study:

• To investigate the nature and strength of non-bonded S...O intramolecular interactions in 2-(phenylthio)acetophenone and 2-(benzylthio)acetophenone.
• To elucidate the contribution of potential resonance structures to the observed bonding.
• To provide insights into the electronic structure of these organosulfur compounds.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the precise molecular structures.
• Computational chemistry methods, likely including density functional theory (DFT), were used to analyze electronic structure and bonding.
• Analysis of bond lengths, bond angles, and non-bonded contacts was performed.

Main Results:

• The non-bonded S...O distances in both 2-(phenylthio)acetophenone and 2-(benzylthio)acetophenone were found to be unusually short.
• These short distances suggest significant attractive interactions between the sulfur and oxygen atoms.
• Electronic structure calculations indicated the involvement of heterocyclic oxathiole-type resonance structures.

Conclusions:

• The unusually short S...O intramolecular interactions are a key feature of these acetophenone derivatives.
• Heterocyclic oxathiole-type resonance structures significantly contribute to the overall bonding in these compounds.
• This study highlights the importance of considering resonance effects in understanding bonding in organosulfur compounds.