Six-Component Molecular Solids: ABC[D_1-(x+y)E_xF_y]₂.

Area of Science:

• Crystal Engineering
• Supramolecular Chemistry
• Materials Science

Background:

• Designing multi-component molecular solids presents significant challenges in controlling crystal packing and stoichiometry.
• Previous strategies often face limitations in achieving higher-order cocrystal formation due to the lack of crystallographic inequivalences.
• The concept of using lower-order cocrystals as stepping stones for higher-order structures is explored.

Purpose of the Study:

• To develop a robust strategy for the synthesis of six-component molecular solids.
• To overcome synthetic limitations encountered in achieving quaternary cocrystals.
• To explore the incorporation of new components into existing crystal lattices.

Main Methods:

• Development of a protocol involving stoichiometric quaternary cocrystal formation.
• Exploitation of crystallographic inequivalences for sequential component substitution.
• Utilizing shape-size similarities of halogenated and methylated resorcinols (e.g., CRES, BRES, MRES) to circumvent synthetic dead ends.
• Incorporation of additional components via solid solution formation.

Main Results:

• A synthetic pathway was established, progressing from binary to higher-order cocrystals.
• A synthetic dead end at the quaternary cocrystal level was identified and overcome.
• Several five- and six-component molecular solids were successfully synthesized.
• The fifth and sixth components were incorporated as solid solutions at the site of the fourth component.

Conclusions:

• The developed strategy enables the rational design and synthesis of complex, multi-component molecular solids.
• Exploiting crystallographic environments and component similarities is key to building intricate supramolecular architectures.
• This approach offers a viable route to novel materials with tunable properties through precise molecular assembly.