Four- and five-component molecular solids: crystal engineering strategies based on structural inequivalence

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Crystallography

Background:

• Co-crystallization is a key method for designing solid-state materials with tailored properties.
• Developing multi-component molecular crystals presents significant synthetic challenges.
• Understanding the structural basis of cocrystal formation is crucial for designing complex systems.

Purpose of the Study:

• To develop a general synthetic strategy for increasing the component number in molecular crystals.
• To utilize specific structural features of lower-component cocrystals for supramolecular homologation.
• To report novel quaternary and quintinary cocrystals.

Main Methods:

• Exploiting differential structural environments of chemical constituents within existing cocrystals.
• Employing 2-Methylresorcinol and tetramethylpyrazine as foundational template molecules.
• Systematic synthesis and characterization of multi-component molecular crystals.

Main Results:

• A successful strategy for the co-crystallization of four- and five-component molecular crystals was established.
• Ten novel stoichiometric quaternary cocrystals and one quintinary cocrystal were synthesized and characterized.
• The concept of 'synthetic dead ends' was identified for cocrystals unsuitable for further homologation.

Conclusions:

• The described strategy enables the rational design and synthesis of complex multi-component molecular crystals.
• This approach expands the toolkit for creating advanced supramolecular materials.
• Further research can explore the application of this strategy to other chemical systems.