Extending the Hammett correlation to mechanochemical reactions

Area of Science:

• Solid-state chemistry
• Physical-organic chemistry
• Mechanochemistry

Background:

• Mechanochemistry enables solvent-free chemical transformations.
• Understanding reaction mechanisms in mechanochemistry is crucial for process optimization.
• Physical-organic chemistry provides established frameworks for analyzing reaction kinetics and substituent effects.

Purpose of the Study:

• To investigate the relationship between reaction probability and electronic effects in a model solid-state mechanochemical reaction.
• To determine the transferability of physical-organic chemistry concepts to mechanochemical processes.
• To establish quantitative structure-activity relationships in ball milling reactions.

Main Methods:

• Raman spectroscopy for in situ reaction monitoring.
• Mechanochemistry-specific kinetic analysis.
• Correlation analysis with Hammett constants.

Main Results:

• A direct correlation was observed between reaction probability and Hammett constants in the mechanochemical imine formation.
• The findings indicate that substituent effects, predictable by Hammett constants, influence reaction outcomes in ball milling.
• The study successfully applied kinetic analysis to a solid-state mechanochemical process.

Conclusions:

• Established principles from physical-organic chemistry are transferable to solid-state mechanochemical reactions.
• Hammett constants can serve as predictive tools for reaction outcomes in ball milling.
• This work opens avenues for rational design and optimization of mechanochemical syntheses.