Bismuth Coordination Polymers with Fluorinated Linkers: Aqueous Stability, Bivolatility, and Adsorptive Behavior

Area of Science:

• Materials Science
• Inorganic Chemistry
• Crystallography

Background:

• Bismuth metal-organic frameworks and coordination polymers (CPs) present synthesis challenges due to precursor insolubility and Bi3+ ligation lability.
• The intrinsic lone pair of Bi3+ contributes to asymmetric and labile coordination, complicating CP construction.

Purpose of the Study:

• To synthesize and structurally characterize novel bismuth coordination polymers (Bi-CPs) using a tetrafluoroterephthalate (F4BDC) linker.
• To investigate the impact of high acidity and mineralizers on the synthesis and assembly of Bi-CPs.
• To evaluate the adsorption properties and thermal stability of the synthesized Bi-CPs.

Main Methods:

• Single-crystal X-ray diffraction for structural characterization of Bi-CPs.
• Powder X-ray diffraction and microscopic imaging for purity and stability assessment.
• Methylene blue adsorption studies and thermogravimetric analysis (TGA) for performance evaluation.

Main Results:

• Three distinct Bi-F4BDC structures were synthesized, featuring Bi chains, dimers, and tetramers, with linker pi-pi stacking influencing framework assembly.
• High purity and aqueous stability were confirmed for the Bi-F4BDC compounds.
• Methylene blue adsorption efficacy varied among phases, with fluorinated ligands contributing to hydrophobicity and improved adsorption.
• TGA revealed simultaneous ligand degradation and volatile bismuth compound formation, suggesting potential for chemical vapor deposition.

Conclusions:

• The tetrafluoroterephthalate linker facilitates the synthesis of stable bismuth coordination polymers.
• Framework structures and adsorption properties are influenced by linker interactions and ligand hydrophobicity.
• The synthesized Bi-CPs demonstrate potential for pollutant adsorption and thin film deposition applications.