Effect of modulator connectivity on promoting defectivity in titanium-organic frameworks.

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Defect chemistry is a key tool for tuning material properties.
• UiO-type materials demonstrate the success of defect engineering.
• Titanium-organic frameworks (Ti-MOFs) are under-explored for defect engineering due to Ti(IV) chemistry challenges.

Purpose of the Study:

• To investigate modulator-assisted defect creation in heterometallic Ti-MOFs.
• To compare the efficacy of mono- and dicarboxylic acids (benzoic and isophthalic acid) in promoting defects.
• To understand the role of linker properties in defect formation and framework stability.

Main Methods:

• Synthesis of MUV-10 family Ti-MOFs using benzoic and isophthalic acid modulators.
• Characterization of defective Ti-MOF phases.
• Computational modeling to analyze structural and energetic effects of defects.

Main Results:

• Both benzoic and isophthalic acids act as capping modulators at high concentrations.
• Isophthalic acid is a more potent defect promoter, generating phases with up to 40% missing linkers.
• Computational analysis indicates isophthalic acid's bidentate nature aids in stabilizing framework distortions caused by missing linkers.

Conclusions:

• Isophthalic acid is a superior modulator for creating defects in Ti-MOFs.
• Defect formation in Ti-MOFs is influenced by linker chemistry beyond simple acidity.
• This work expands defect engineering strategies to titanium-based metal-organic frameworks.