Proton conductive metal sulfonate frameworks

Porosity regulation of metal–organic frameworks for high proton conductivity by rational ligand design: mono- versus disulfonyl-4,4′-biphenyldicarboxylic acid

“…18 Consequently, sulfonated materials can interact with water molecules forming proton clusters in the form of –SO 3 − ⋯H 3 O + and significantly increase the proton conductivity in a low RH environment. 19 Several methods for anchoring the acidic sulfonic groups to MOF pores have been developed including sulfonation of MOFs via post-synthesis, 20–22 sulfonation of organic linkers, 23 and coordination of sulfonic acid to metal centres. 24,25 Unfortunately, the modified MOFs are seldom examined by single crystal X-ray diffraction analysis; as a result, an in depth understanding of the precise H-bonding networks and proton conducting pathway is difficult.…”

“…Sulfonic group substituted carboxylic ligands can be regarded as appealing candidates for the construction of proton conductive MOFs and some MOFs have also been characterized by single crystal X-ray diffraction analysis. 19,26 Commonly used ligands for the preparation of proton conductive MOFs include dipotassium-3,3′-disulfonyl-4,4′-biphenyldicarboxylic acid (3,3′- DSBPDC ), 27 3,3′-disulfonyl-benzophenone-4,4′-dicarboxylic acid ( DSBODC ), 28 3,3′-disulfonyl-diphenylsulfone-4,4′-dicarboxylic acid ( DSDPSDC ), 29 disodium 2,2′-disulfonate-4,4′-oxydibenzoic acid ( DSOA ), 30–32 and 2,2′-disulfonyl-4,4′-biphenyldicarboxylic acid (2,2′- DSBPDC ). 33,34 All these ligands have two sulfonyl groups, which can be easily deprotonated to bind metal centers due to the stronger chelating ability of –SO 3 − groups to form cyclic coordinated configurations with neighboring –CO 2 − or –SO 3 − groups (Scheme 1).…”

“…33,34 All these ligands have two sulfonyl groups, which can be easily deprotonated to bind metal centers due to the stronger chelating ability of –SO 3 − groups to form cyclic coordinated configurations with neighboring –CO 2 − or –SO 3 − groups (Scheme 1). 19,35 The coordination of the –SO 3 − group to metal centers will reduce the proton concentration and the porosity of the resulting MOFs, so that the proton conductivity may be greatly decreased. 28…”

The role of sulfonate groups and hydrogen bonding in the proton conductivity of two coordination networks

“…Recent achievements in the synthesis of advanced functional materials with tailored, structure-related physical properties have stimulated the development of new concepts and devices for energy storage [ 1 – 2 ] and energy conversion [ 3 – 4 ]. Among these, proton-conducting solid materials show significant potential in the development of novel membranes for proton exchange membrane (PEM) fuel cells, PEM electrolyzers, and for humidity sensors [ 5 – 7 ]. The goal is to overcome the restrictions of state-of-the-art proton-conducting membrane materials such as Nafion.…”

Dual-Functional Coordination Polymer with High Proton Conductivity and a Low-Detection-Limit Fluorescent Probe

“…Efficient proton-conductive materials are very important for PEMFCs. Coordination polymers have been used in the preparation of proton-conductivity materials due to their structural diversity, large specific surface area, high porosity, flexibility, and abundant chemical components. − The CPs can be used to present the structure of the material at the atomic level via X-ray diffraction technology due to its high crystallinty, thereby giving the detailed structure information on the material, which provides the possibility to study the transfer mechanism of proton-conducting materials at the atomic level. By clarifying the mechanism of proton conduction, it can provide an important reference for the deep design of proton-conductivity materials with excellent performance.…”