Facile Synthesis of Enzyme-Mimicking Cobalt-Polyphenol Coordination Network for Oxidation of Phenolic Pollutants

Abstract

Owing to the multiple biological properties and applications associated with plant-based polyphenols, the development of higher-order hierarchical superstructures utilizing polyphenols as building blocks is of immense scientific interest. Polyphenol-based materials possess applications in the fields of cell biology, cancer theranostics, drug delivery, photothermal therapy, etc. Herein, we report the sustainable synthetic strategy to engineer a functional material via the coordination between ellagic acid (EA) and Co(II) ions under ambient reaction conditions. The self-assembly of Co-EA coordination networks led to crosslike superstructures of average dimension ∼1 μm. The redox nature of Co(II) centers and the electron mediating property of EA enabled the Co-EA network to display excellent activity for mimicking the multicopper oxidase enzymes, namely, laccase and phenoxazinone synthase with considerably lower K m values than the native enzymes. The heterogeneous nature of the Co-EA was validated by its stability as well as better recyclability during the phenoxazinone synthase enzymatic reaction. Additionally, the oxidative degradation of various phenolic pollutants was carried out at ambient conditions using the laccase-mimicking activity of the Co-EA network. Considering their cost-effective facile synthesis, robust activity, stability, and recyclability, this polyphenol-based functional material can be explored for various applications such as a heterogeneous catalyst for organic transformations and environmental remediation.