Isolated Co15 clusters and their assembly into a 3D network: conformation-directed synthesis

Area of Science:

• Materials Science
• Coordination Chemistry
• Supramolecular Chemistry

Background:

• Metal-organic frameworks (MOFs) offer tunable structures for various applications.
• Controlling the conformation of organic linkers is crucial for designing MOF architectures.
• Cobalt-based clusters are of interest for catalytic and magnetic properties.

Purpose of the Study:

• To synthesize and characterize a novel 3D coordination network using cobalt clusters.
• To investigate the role of the linker's conformation (cis vs. trans) in network formation.
• To explore the structural diversity achievable with multifunctional organic linkers.

Main Methods:

• Solvothermal synthesis of cobalt clusters with organic linkers.
• Single-crystal X-ray diffraction for structural determination.
• Infrared spectroscopy and elemental analysis for characterization.

Main Results:

• Isolated clusters of 15 cobalt atoms were formed, linked by organic molecules containing carboxylic and phosphonic groups.
• The trans conformation of cyclohexanehexacarboxylic acid acted as counteranions.
• The cis conformation of cyclohexanehexacarboxylic acid coordinated to cobalt clusters, replacing water ligands and forming a 3D network.

Conclusions:

• The study demonstrates the successful synthesis of a cobalt-based 3D coordination network.
• The conformation of the organic linker plays a critical role in dictating the final network topology.
• This work expands the library of MOFs with potential applications in gas storage or catalysis.