Two- and three-fold interpenetrated metal-organic frameworks from one-pot crystallization

Area of Science:

• Coordination Chemistry
• Materials Science
• Crystallography

Background:

• Metal-organic frameworks (MOFs) are porous crystalline materials with diverse applications.
• Interpenetration in MOFs leads to complex network topologies and altered properties.
• Designing MOFs with controlled interpenetration remains a significant challenge.

Purpose of the Study:

• To synthesize and characterize two distinct three-dimensional interpenetrating MOFs.
• To investigate the influence of reaction conditions on MOF topology and interpenetration.
• To explore the concept of supramolecular isomerism in coordination polymers.

Main Methods:

• One-pot co-crystallization of metal-organic frameworks.
• Single crystal X-ray diffraction analysis for structural determination.
• Variable parameter screening (solvent, countercation, component order) to control isomer formation.

Main Results:

• Two novel cobalt-based MOFs, {[Co(bpe)(muco)](DMF)(H 2O)} n (1) and {[Co(bpe)(muco)(H 2O) 2].4(H 2O)} n (2), were successfully synthesized.
• Compound 1 exhibits a 2-fold interpenetrated alpha-Po net, while compound 2 displays a 3-fold interpenetrating network with an unprecedented 6(6) topology.
• Both MOFs feature open channels capable of hosting guest solvent molecules, and can be considered supramolecular isomers.

Conclusions:

• The study demonstrates the intricate design of coordination polymers with variable interpenetration and novel network topologies.
• Control over isomer formation can be achieved by manipulating reaction parameters.
• These findings provide valuable insights into the rational design of complex MOF structures.