Thiol and thioether-based metal-organic frameworks: synthesis, structure, and multifaceted applications.

Area of Science:

• Materials Science
• Chemistry

Background:

• Metal-organic frameworks (MOFs) are hybrid porous materials constructed from metal ions and organic linkers.
• Thiol and thioether-based MOFs represent a specialized class, incorporating sulfur functionalities within their organic linkers.

Purpose of the Study:

• To systematically categorize thiol and thioether-based MOFs based on the structural role of sulfur-containing groups in the organic linkers.
• To review and present established and emerging synthetic methodologies for these MOFs.
• To consolidate knowledge on the properties and potential applications of these sulfur-functionalized MOFs.

Main Methods:

• Classification of thiol-thioether MOFs into three categories based on linker composition: carboxylic acid ligands, sole organic linkers, or azolate-containing linkers.
• Review of direct synthesis approaches utilizing thiol/thioether carboxylic acid ligands, considering ligand-metal interactions (HSAB principle) and resulting structural motifs.
• Discussion of indirect synthesis strategies, including post-synthetic modification (PSM) and post-synthetic exchange (PSE), as well as composite material formation.

Main Results:

• Thiol-thioether MOFs with carboxylic acid ligands can exhibit common structural motifs (e.g., UiO, MIL, NU series) or unique structures.
• MOFs solely comprising thiol-thioether ligands, often synthesized via interfacial methods, demonstrate high electrical conductivity.
• Limited research exists on MOFs with thiol-thioether azolate ligands, yet they show promise due to the interplay of nitrogen and sulfur functionalities.

Conclusions:

• Thiol and thioether-based MOFs present diverse structural possibilities and tunable properties.
• These materials hold significant potential for applications in catalysis, sensing, conductivity, and adsorption.
• Further research into MOFs with azolate ligands and exploration of novel synthetic routes are encouraged.