Hydrogen bond contribution to preferential solvation in S(N)Ar reactions

Area of Science:

• Organic Chemistry
• Physical Chemistry
• Solvation Science

Background:

• Aromatic nucleophilic substitution reactions are fundamental in organic synthesis.
• Understanding solvent effects is crucial for controlling reaction rates and mechanisms.
• Preferential solvation influences reaction pathways and kinetics.

Purpose of the Study:

• To investigate preferential solvation in aromatic nucleophilic substitution reactions.
• To elucidate the role of solvent composition on reaction kinetics.
• To correlate kinetic data with quantum chemical calculations.

Main Methods:

• Kinetic study of secondary alicyclic amines reacting with phenyl 2,4,6-trinitrophenyl ether.
• Systematic variation of aqueous ethanol mixture compositions.
• Quantum chemical calculations to support experimental findings.
• Solvent effect studies to analyze solvation behavior.

Main Results:

• Piperidine exhibited significant sensitivity to solvation effects.
• Other secondary alicyclic amines showed less sensitivity to solvent composition.
• The observed sensitivity in piperidine was linked to the mixture's polarity.
• Evidence for specific electrophilic solvation in the aqueous phase was found.

Conclusions:

• Preferential solvation plays a distinct role in aromatic nucleophilic substitution reactions.
• Piperidine's reactivity is modulated by specific solvation interactions.
• The findings highlight the importance of solvent polarity in governing reaction outcomes.
• Electrophilic solvation in aqueous media influences the reaction mechanism.