An Ultra-Stable Cr-Hydroxamate Metal-Organic Framework From Postsynthetic Transmetalation

Area of Science:

• Materials Science
• Inorganic Chemistry
• Nanotechnology

Background:

• Hydroxamate-based metal-organic frameworks (MOFs) offer strong chelation but lack the stability of carboxylate MOFs.
• Developing robust hydroxamate MOFs is crucial for advanced applications.

Purpose of the Study:

• To synthesize novel, stable hydroxamate-based MOFs using a tris-hydroxamic acid linker (H3TATPHA).
• To investigate the stability and functionality of these MOFs, particularly after postsynthetic modification.

Main Methods:

• Synthesized isostructural MOFs (SUM-86) with Ga(III), In(III), and Fe(III) using H3TATPHA.
• Performed single-crystal-to-single-crystal transmetalation of SUM-86(In) with Cr(III) to yield SUM-86(Cr).
• Assessed the chemical stability of SUM-86(Cr) in harsh conditions and its iodine adsorption capabilities.

Main Results:

• A family of isostructural MOFs (SUM-86) with a two-fold interpenetrated srs topology was successfully synthesized.
• Nearly quantitative, single-crystal-to-single-crystal transmetalation yielded highly stable SUM-86(Cr) MOFs.
• SUM-86(Cr) demonstrated exceptional stability in boiling water, 3 M HCl, and 5 M NaOH, and exhibited rapid, high-capacity iodine adsorption.

Conclusions:

• Postsynthetic transmetalation is an effective strategy for enhancing the stability of hydroxamate-based MOFs.
• The resulting ultra-stable SUM-86(Cr) MOFs show promise for applications like iodine capture.