Penta-nuclear [Ag5I6] Cluster-Based Photochromic Hybrid: Synthesis, Structure, Dye Sorption, and Separation

Abstract

An [Ag5I6] cluster-based coordination polymer has been successfully constructed with the assistance of a polydentate organic amine hexamethylenetetramine (Hmta) as the linker, [NH4][Ag5I6(Hmta)] (1). Compound 1 features an anionic 2D bilayer network wherein the combination of Ag(I) with I– and N atom gives rise to a novel [Ag5I6] secondary building unit and further generates the final architecture with free NH4+ being located in the space of the framework. Interestingly, compound 1 exhibits a cation exchange behavior which can efficiently capture and separate methylene blue (MB) in a binary mixture of dye solution. Desorption experiments have been performed, showing that the MB molecules in dye-loaded samples can be readily discharged when triggered by Na+. Moreover, reversible photochromism is observed for solid 1, displaying a rapid color response to light illumination.