PEGylated Metalloporphyrin Nanoparticles as a Promising Catalyst for the Heterogeneous Oxidation of Cyclohexene in Water

• Published in: Macromolecular chemistry and physics Vol. 216; no. 4; pp. 417 - 426
• Main Authors: Xu, Li Qun, Chen, Jiu Cun, Qian, Shan Shan, Zhang, Ao Kai, Fu, Guo Dong, Li, Chang Ming, Kang, En-Tang
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01.02.2015; Wiley Subscription Services, Inc
• Subjects: amphiphilic block copolymers; Block copolymers; Catalysts; Catalytic activity; catalytic oxidation; copper(I)-catalyzed azide-alkyne cycloaddition; Dissolution; Nanoparticles; Oxidation; Polymerization; Self assembly; Solvents
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.201400477

Amphiphilic poly[poly(ethylene glycol) methyl ether methacrylate]‐b‐poly(azidopropyl acrylamide) (PPEGMEMA‐b‐PAzPA) block copolymers are synthesized via a combination of reversible addition‐fragmentation chain transfer (RAFT) polymerization and a reactive ester‐amine reaction. The azido‐functionalized PPEGMEMA‐b‐PAzPA block copolymers can self‐assemble into polymeric micelles in an aqueous medium and encapsulate hydrophobic alkynyl‐containing manganese(III)porphyrin (MnP) within the core domain. The subsequent in situ copper(I)‐catalyzed azide‐alkyne cycloaddition (CuAAC) leads to the formation of PEGylated‐MnP nanoparticles (PEG‐MnP NPs). The as‐synthesized PEG‐MnP NPs are explored as a heterogeneous catalyst for oxidation of cyclohexene in water. The effect of various parameters, such as precursor oxidants, substrate to catalyst loading ratio, and presence of a cocatalyst, is investigated to optimize the oxidation conditions. The catalytic activity of PEG‐MnP NPs in water is also compared with that of dissolved MnP in organic solvent. Metalloporphyrins are extensively utilized as biomimetic cytochrome P450 models for catalytic oxidation. However, most metalloporphyrins are hydrophobic. PEGylated‐metalloporphyrin nano­particles are prepared via a combination of controlled radical polymerization, reactive ester‐amine reaction, and in situ self‐assembly and “click” cross‐linking. The resulting PEGylated‐metalloporphyrin nanoparticles in water exhibit a higher catalytic activity than the dissolved metallo­porphyrin in organic solvent.