Constructing Water-Stable Porous Organic Salts via Suppressed Proton Integration Using Fluorinated Tetrazole Tectons.

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Chemical Engineering

Background:

• Porous organic salts (POSs) exhibit promising proton transfer and water uptake but suffer from poor stability in aqueous environments due to strong hydrogen bonding.
• Conventional synthesis methods using strong acids and bases create POSs susceptible to water-induced degradation, limiting their practical applications.

Purpose of the Study:

• To design and synthesize novel POSs with enhanced stability in both aqueous and water-lean conditions.
• To develop a new synthetic strategy for POSs that minimizes hydrogen bonding with water and relies on cation-anion interactions for structural integrity.

Main Methods:

• Utilized a weak acid (fluorinated tetrazole) and a proton-devoid base (tetra-substituted imidazole precursor) for POS synthesis.
• Employed single-crystal X-ray diffraction and computational modeling to analyze structural features and water interactions.
• Verified structural robustness using X-ray and neutron scattering techniques under various humidity conditions.

Main Results:

• Synthesized POSs with hydrophobic porous channels and minimal hydrogen bonding, confirmed by structural analysis.
• Demonstrated that structural integrity is maintained through cation-anion interactions, with water forming non-interacting clusters within pores.
• Confirmed structural robustness under aqueous and water-lean conditions via scattering experiments and computational modeling.
• Showcased the stability and efficacy of the new POSs in aqueous iodine capture, highlighting the role of imidazolium cations and C-F groups as adsorption sites.

Conclusions:

• The developed approach successfully creates robust POS materials stable in diverse aqueous and water-lean environments.
• This strategy overcomes the limitations of conventional POSs, expanding their potential applications in separation and catalysis.
• The design principles offer a pathway for engineering next-generation porous materials with tailored stability and functionality.