Stable Polyoxometalate-Based Metal-Organic Framework: Synthesis, Modification, and Catalytic Activity

Area of Science:

• Materials Science
• Inorganic Chemistry
• Catalysis

Background:

• Metal-organic frameworks (MOFs) incorporating polyoxometalates (POMs) offer high stability.
• MOFs with accessible channels and modifiable groups are promising catalytic platforms.
• Functionalization of MOFs can enhance their catalytic properties.

Purpose of the Study:

• To synthesize and characterize a novel POMOF with a large channel structure.
• To investigate the stability and catalytic activity of the pristine POMOF.
• To functionalize the POMOF with palladium (Pd) for enhanced catalytic applications.

Main Methods:

• Synthesis of a polyoxometalate-based metal-organic framework (POMOF), [Ni(en)₂]₄H{[Ni₆(tris)(en)₃(SIP)_1.5][B-α-PW₉O₃₄]}₂·32H₂O (1).
• Characterization of stability using immersion experiments, in situ variable temperature powder X-ray diffraction, and dehydration-hydration studies.
• Modification of POMOF 1 with palladium species (1-Pd) and evaluation of catalytic activity in Suzuki-Miyaura coupling reactions.

Main Results:

• The synthesized POMOF (1) possesses a large channel (ca. 1.1 × 1.8 nm) lined with amino groups.
• Compound 1 exhibits excellent thermal and chemical stability, confirmed by various experimental methods.
• Pristine 1 shows high activity in the hydrogen evolution reaction, and the Pd-loaded material (1-Pd) effectively catalyzes Suzuki-Miyaura coupling reactions.

Conclusions:

• The novel POMOF 1 is a stable and functionalizable material with potential for catalytic applications.
• The amino groups within the POMOF channels facilitate palladium loading and catalytic activity.
• The Pd-functionalized POMOF (1-Pd) is a promising heterogeneous catalyst for Suzuki-Miyaura coupling reactions.