Coordination polymer gels: soft metal–organic supramolecular materials and versatile applications

Abstract

In recent times, significant attention has been paid to the development of functional coordination polymer gels (CPGs) from rationally designed low molecular weight gelators (LMWGs) and metal ions. Coordination of metal ions to LMWGs provides an opportunity to emulate metal based redox, optical, electronic and magnetic properties in soft CPG materials. The metal-LMWG interactions allow controlled growth of CPGs with different nanostructures such as fibers, tubes, rings, ribbons and vesicles. Furthermore, the nanoscale periodicity of metal ions and LWMGs in CPGs is of paramount importance for different optoelectronic applications. The easy processability and dynamic nature of CPGs are explored for application in diverse fields, including drug-delivery, gas storage, optoelectronics, chemo-sensing, self-healing, etc. Also, by taking advantage of dynamic metal-ligand coordination bonds various stimuli-responsive multi-functional CPGs are developed. In this feature article, we cover important examples of newly developed CPGs, which show potential applications in different fields.

Redox‐Induced Molecular Metamorphism Promoting a Sol/Gel Phase Transition in a Viologen‐Based Coordination Polymer

“…At this stage, one should however be cautious about correlating the sol/gel phase change to a specific reorganization process. Gel formation implies the existence of three‐dimensional networks but there are precedents in literature showing that metal‐organic gels can as well involve discrete molecules or coordination polymers . In the absence of further information, it is thus still not clear whether reduction leads to a dissociation of the self‐assembled coordination polymer to yield discrete/macrocyclic compounds or to a drastic change in the organization of the tectons within the polymeric assemblies (Figure ).…”

Transforming HKUST‐1 Metal–Organic Frameworks into Gels – Stimuli‐Responsiveness and Morphology Evolution

“…Despite its numerous advantages, the application of HKUST‐1 in device fabrication and biological uses is still limited by the low solution processability of crystalline MOFs. To enhance the processing capabilities of porous materials, soft coordination polymer gels or MOF gels may be superior alternatives to conventional MOFs owing to the reversible sol–gel behavior of these systems …”

“…To enhance the processing capabilities of porous materials, soft coordination polymer gels or MOF gels may be superior alternatives to conventional MOFs owing to the reversible sol-gel behavior of these systems. [9] To date, major advances in supramolecular gels, [10] in particular metallogels, [9,11] have triggered a wave of discoveries of vestigated through a combination of electron microscopy, Xray analysis techniques, and optical spectroscopy. A continuous morphology evolution was confirmed to exist for a gradual decrease of the molar ratio between the metal and the ligand.…”

Metal‐Organic Gel‐Derived Co/CoO/Co3O4 Composite for the Electrochemical Detection of Diethylstilbestrol

“…Metal‐organic gel (MOG) is also called the coordination polymer gel, which is assembled by gelator to form gel network structure, and the metal‐ligand coordination bond, hydrogen bond, π‐π stacking, and van der Waals force are the mainly interaction manners . MOG materials have been broadly applied in the drug carrier, sensor, catalysis and luminescence field owning to the properties of good compatibility, stimuli‐responses, high surface areas, inherently present open metal sites and large channels .…”