Site-Selective Catalytic Epoxidation of Alkenes with Tunable Atomic Precision by Molecularly Imprinted Artificial Epoxidases

Abstract

Distinction of chemical functionality by their local chemical environment is a skill mastered by enzymes, evident from the selective synthesis, cleavage, and transformation of peptides, nucleic acids, and polysaccharides that abound with the same type of functional group. In contrast, synthetic catalysts are generally better at differentiating functional groups based on their electronic and steric properties. Here, we report artificial epoxidases prepared through the molecular imprinting of surface–core doubly cross-linked micelles, followed by efficient functionalization of the imprinted site in the micellar core via photoaffinity labeling. The size and shape of the active sites are tuned by the modularly synthesized templates, with the oxygen-delivering peroxy acid group positioned accurately. These catalysts are used in the epoxidation of alkenes in water with hydrogen peroxide under mild conditions without any additional additives. Most importantly, atomic precision is achieved in the catalysis and enables alkenes to be distinguished that differ in the position of the carbon–carbon double bond by a single carbon.

Synergistic Hydrolysis of Cellulose by a Blend of Cellulase-Mimicking Polymeric Nanoparticle Catalysts

“…Phenyl azides with fluoro groups at the 2,6-positions are well-known photoaffinity labels. Under photolysis, they form nitrenes that undergo C–H insertion readily, especially efficiently in a hydrophobic microenvironment of an imprinted pocket. , The micellar core of NP 7 has many C–H bonds from polymerized surfactants and DVB. Because the two carboxylic acids from the isophthalic acid moiety of 10 is supposed to occupy the space imprinted from the two meta nitro groups of the template, they should sandwich the exocyclic glycosidic oxygen of the third glucose unit in a bound cellulose to promote its hydrolysis.…”

Recent development in the design of artificial enzymes through molecular imprinting technology

“…Analogously, Zhao's group developed a site-selective artificial epoxide oxidase by micelle imprinting. 97 When the template is removed, the formed imprinted sites generate peroxycarboxylic acid in situ under UV light irradiation, thus precisely fixing the catalytic site within the imprinted pockets. By adjusting the synthesized templates, the size and shape of the imprinted sites can also be regulated, and the position of the catalytic sites can be precisely located, allowing the prepared artificial enzymes to distinguish alkenes whose carbon-carbon double bond positions differ by one carbon.…”

pH-Responsive epitope-imprinted magnetic nanoparticles for selective separation and extraction of chlorogenic acid and caffeic acid in traditional Chinese medicines

“…Especially, strong molecular recognition properties make it easy to separate structural analogues. MIPs have been widely applied in separation, 14,15 catalysis, 16,17 sensing 18,19 and cancer therapy. 20,21 So far, many MIPs have been synthesized for the selective recognition of chlorogenic acid and caffeic acid.…”