Freeze the dynamicity: charge transfer complexation assisted control over the reaction pathway

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry

Background:

• Charge transfer (CT) complexes, featuring donor-acceptor (D-A) arrangements, offer unique molecular structures.
• The dynamic nature of CT complexes in solution limits their application in chemo-selective organic transformations due to co-existing free monomers.

Purpose of the Study:

• To develop a novel strategy for exploiting CT complexes to achieve chemo-selective organic transformations.
• To overcome the limitations posed by the dynamicity of CT complexes in solution.

Main Methods:

• Aqueous CT complexes of donor and acceptor molecules with reactive thiol groups were prepared.
• These complexes were rapidly frozen and cryo-desiccated to preserve the D-A assemblies in a solid state.
• Solid-state oxidation of thiols in an oxygen-rich solvent was employed to induce reaction.

Main Results:

• The cryo-desiccation method successfully preserved the CT complex assemblies in the solid state.
• Solid-state oxidation exclusively yielded hetero-dimers, demonstrating high chemo-selectivity.
• The methodology proved effective in synthesizing unsymmetrical disulfide molecules from two different thiols.

Conclusions:

• Seizing the dynamicity of CT complexes by solid-state preservation is a viable strategy for chemo-selective synthesis.
• CT complexation and precise molecular arrangement are crucial for the success of this method.
• This approach provides a new route for preparing unsymmetrical disulfide compounds.