Metal-Terpyridine Assembled Functional Materials for Electrochromic, Catalytic and Environmental Applications

Molecular assembly induced by metal-terpyridine-based coordinative interactions has become an emergent research topic due to its ease of synthesis and diverse applications. This article highlights recent significant developments in the metal-terpyridine-based supramolecular architectures. At first, the design aspect of the molecular building blocks has been described, followed by elaboration on how the ligand backbone plays an important role for achieving different dimensionalities of the resulting assemblies which exhibit a wide range of potential applications. After that, we discussed different synthetic approaches for constructing these assemblies, and finally, we focused on their significant developments in three specific areas, viz., electrochromic materials, catalysis and a new application in wastewater treatment. In the field of electrochromic materials, these assemblies made important advancements in various aspects like sub-second switching time (<1 s), low switching voltage (<1 V), increased switching stability (>10000 cycles), tuning of multiple colors by using multimetallic systems, fabrication of charge storing electrochromic devices, utilizing and storing solar energy etc. Similarly, the catalysis field witnessed application of the metal-terpyridine assemblies in C-H monohalogenation, heterogeneous Suzuki-Miyaura coupling, photocatalysis, reduction of carbon dioxide, etc. Finally, the environmental application of these coordination assemblies includes capturing Cr(VI) from waste water efficiently with high capture capacity, good recyclability, wide pH independency etc.