Switched Proton Conduction in Metal–Organic Frameworks

Abstract

Stimuli-responsive materials can respond to external effects, and proton transport is widespread and plays a key role in living systems, making stimuli-responsive proton transport in artificial materials of particular interest to researchers due to its desirable application prospects. On the basis of the rapid growth of proton-conducting porous metal–organic frameworks (MOFs), switched proton-conducting MOFs have also begun to attract attention. MOFs have advantages in crystallinity, porosity, functionalization, and structural designability, and they can facilitate the fabrication of novel switchable proton conductors and promote an understanding of the comprehensive mechanisms. In this Perspective, we highlight the current progress in the rational design and fabrication of stimuli-responsive proton-conducting MOFs and their applications. The dynamic structural change of proton transfer pathways and the role of trigger molecules are discussed to elucidate the stimuli-responsive mechanisms. Subsequently, we also discuss the challenges and propose new research opportunities for further development.

Water-driven reversible switching of single-ion magnetism and proton conduction in a dysprosium sulfonate

“…Dynamic molecular crystals with switchable physical properties, such as magnetic, electronic, optical, and mechanical, have attracted great attention for their potential applications in molecular devices. 1 To date, many molecular materials have been reported to exhibit dynamic modification or switching of their physical properties achieved using several physical or chemical methods, such as stimuli-induced structural changes, 2 orientational changes, 3 light irradiation, 4 and so on. Among those ways, the switched processes using reversible single-crystal-to-single-crystal (SC–SC) transformation are particularly appealing because the atomically precise crystal structures provide opportunities for detailed studies on structure–function relationships.…”

Solid-State Proton Conduction Driven by Coordinated Water Molecules in Metal–Organic Frameworks and Coordination Polymers

“…Although quite a few reviews on proton-conducting MOFs and CPs have already appeared in the literature, focusing on various aspects of their chemistries such as design principles, ,,− ligands used (carboxylate/phosphonate), , conducting media, − switching behavior, and so on, − none of these reviews has focused on proton conduction driven by coordinated water molecules where the metal-bound water molecules act as a sole intrinsic protonic source . This analysis therefore reveals the scope of writing a Perspective solely based on those developed proton-conducting MOFs and CPs where coordinated water molecules act as a solitary proton source because of its enhanced acidity while bound to metal centers and thus making the framework conductive for protons.…”

A Proton Conducting Cobalt(II) Spin Crossover Complex

“…However, after these interesting studies, conducting Co II SCO compounds was barely explored. Regarding conducting materials, proton‐conducting materials have gained increasing interest due to their significant applications for electrochemical devices [17–19] . Proton‐conductive magnetic compounds have been studied for years and led to a lot of fascinating multifunctional materials, including proton‐conductive magnetic ordering materials [20–25] .…”