Linear Oligosulfoxides: Synthesis and Solubility Studies

Area of Science:

• Organic Chemistry
• Polymer Science
• Materials Science

Background:

• Sulfoxide groups are highly polar, typically conferring good solubility in polar solvents.
• Linear oligomers' solubility can be influenced by factors beyond simple polarity, such as molecular conformation.
• Understanding solubility patterns is crucial for the application of novel chemical structures.

Purpose of the Study:

• To synthesize linear oligosulfoxides with multiple sulfoxide functionalities.
• To investigate the solubility behavior of these novel oligosulfoxides.
• To explore the relationship between molecular structure, conformation, and solubility.

Main Methods:

• Oligosulfides were synthesized via sequential S_N2 reactions between alkanethiols and alkyl tosylates.
• Oligosulfides were oxidized to oligosulfoxides using sodium periodate, carefully controlling conditions to prevent partial or over-oxidation.
• Solubility of the synthesized oligosulfoxides was tested in various solvents, including DMSO and water.

Main Results:

• Linear oligosulfoxides containing up to six sulfoxide groups were successfully synthesized.
• The synthesized oligosulfoxides demonstrated limited solubility in polar solvents like DMSO and water, contrary to expectations based on the 'like dissolves like' rule.
• The solubility was discussed in comparison to polyethylene glycol (PEG) and other polyethers, highlighting potential conformational influences.

Conclusions:

• The unexpected solubility of oligosulfoxides suggests that molecular conformation plays a significant role in the dissolution process of linear oligomers.
• The findings challenge the direct application of the 'like dissolves like' rule for these specific structures and propose a dissolution model based on conformational compatibility with the solvent.
• The limited solubility observed in this study may not be indicative of all similar oligosulfoxide molecules, suggesting further investigation into structure-solubility relationships is warranted.