Direct observation of intermediates in a thermodynamically controlled solid-state dynamic covalent reaction

Area of Science:

• Solid-state chemistry
• Materials science
• Supramolecular chemistry

Background:

• Polymorph interconversion is crucial for material properties.
• Controlling solid-state transformations remains challenging.
• Dynamic covalent chemistry (DCC) offers new possibilities for molecular manipulation.

Purpose of the Study:

• To investigate polymorph interconversion using solid-state DCC.
• To explore the mechanistic pathways of solid-state reactions.
• To understand the factors influencing polymorphic stability.

Main Methods:

• Solid-state dynamic covalent chemistry (DCC).
• Mechanochemical techniques for inducing interconversion.
• Experimental characterization of dynamic equilibrium.

Main Results:

• Demonstrated polymorph interconversion via reversible covalent chemistry intermediates.
• Identified facilitation of interconversion by disulfide homodimers.
• Confirmed dynamic equilibrium, showing milling conditions affect relative polymorph stability.

Conclusions:

• Solid-state DCC provides a novel route for polymorph interconversion.
• Surface solvation and high surface-to-volume ratio influence polymorphic stability.
• This work opens new avenues for designing and controlling crystalline materials.