A 3D MOF with Cu₂₀/Cu₆ Clusters: Self-Assembly, CO₂ Encapsulation, Structural Features, and Magnetic Properties

Area of Science:

• Inorganic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Multicopper clusters are crucial in inorganic chemistry, biomedical science, and functional materials.
• Designing molecular structures of multicopper clusters is an active area of research.

Purpose of the Study:

• To synthesize and characterize novel multicopper compounds using fluorinated carboxylates and 1,3,5-triaza-7-phosphaadamantane (PTA).
• To investigate the structural, magnetic, and electronic properties of the synthesized compounds.
• To explore the influence of fluorinated carboxylates and atmospheric conditions on the self-assembly of copper clusters.

Main Methods:

• Self-assembly synthesis of copper compounds.
• Single-crystal X-ray diffraction for structural determination.
• Magnetic susceptibility measurements.
• Density Functional Theory (DFT) calculations.

Main Results:

• Formation of a tetranuclear copper cluster [Cu4II(μ3-OH)2(μ-L)6(PTA=O)2] (1) from copper(II) monofluoroacetate.
• Synthesis of a unique 3D metal-organic framework [{Cu20II(CO3)(μ3-O)2(μ3-OH)22(μ-L')12}{Cu6I(μ3-PTA)6(CH3CN)12}]n·6n(L')·3n(H2O)·2n(CH3CN) (2) from copper(II) trifluoroacetate, incorporating atmospheric CO2.
• Both compounds exhibit dominant antiferromagnetic interactions.
• DFT calculations confirm the antiferromagnetic ground state of 1 and the stability of the Cu20 core in 2.

Conclusions:

• The study successfully synthesized two novel multicopper compounds with distinct architectures.
• Fluorinated carboxylates and atmospheric CO2 play significant roles in directing the self-assembly and structure of these copper compounds.
• The findings contribute to the expanding library of multicopper clusters and metal-organic frameworks.