Synthesis of Crystalline Porous Organic Salts

Liuxi Yang1,2, Bao-Lian Su1,2

1 Laboratory of Inorganic Materials Chemistry, University of Namur
Namur Institute of Structured Matter (NISM), University of Namur


The preceding years have experienced the booming development of porous materials in a wide range of fields, from the inorganic skeleton of zeolites, activated carbon, silica, to hybrid metal–organic frameworks (MOFs)1, covalent organic frameworks (COFs), conjugated microporous polymers (CMPs), covalent triazine frameworks (CTFs), and porous aromatic frameworks (PAFs). Although these porous materials exhibit advantages in scientific fields, porous materials with rigid structure and permanent porosity have been rarely reported. Crystalline porous organic salts (CPOSs) are a new member of porous materials and constructed by ionic bonding and hydrogen bonding between organic acid and base2. Because of the special ionic bond, CPOSs provide the confined channels for transportation of high polar molecules which makes them distinct from other porous organic materials (POMs). Aside from that, CPOSs possess permanent porosity that means voids show long-term stability and reversibly accessibility after removing guest molecules. Generally, permanent porosity correlated closely with the strength of ionic bonding and rigidity of framework. However, it is worth to notice that ionic bond is non-directional, which makes the joint of framework too flexible to sustain high intermolecular free volume. Hydrogen bond is a powerful intermolecular force and more importantly, it is directional which can deteriorate flexibility resulting from non-directional ionic bond. The CPOSs with high polarity channel and new promising applications have become a new family of porous organic frameworks3.


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(2) Xing, G.; Yan, T.; Das, S.; Ben, T.; Qiu, S. Synthesis of Crystalline Porous Organic Salts with High Proton Conductivity. Angew Chem Int Ed Engl 2018, 57 (19), 5345-5349. DOI: 10.1002/anie.201800423.

(3) Ami, T.; Oka, K.; Tsuchiya, K.; Tohnai, N. Porous Organic Salts: Diversifying Void Structures and Environments. Angew Chem Int Ed Engl 2022, 61 (31), e202202597. DOI: 10.1002/anie.202202597  From NLM PubMed-not-MEDLINE.