Oxidation chemistry of poly(ethylene glycol)-supported carbonylruthenium(ii) and dioxoruthenium(vi) meso-tetrakis(pentafluorophenyl) porphyrin

Abstract

[Ru11(F20-tpp)(CO)] (1, F20-tpp = meso-tetrakis(pentafluorophenyl)porphyrinato dianion) was covalently attached to poly(ethylene glycol) (PEG) through the reaction of 1 with PEG and sodium hydride in DMF. The water-soluble PEG-supported ruthenium porphyrin (PEG-1) is an efficient catalyst for 2,6-Cl2pyNO oxidation and PhI=NTs aziridination/amidation of hydrocarbons, and intramolecular amidation of sulfamate esters with PhI (OAc)2. Oxidation of PEG-1 by m-CPBA in CH2C12, dioxane, or water afforded a water-soluble PEG-supported dioxoruthenium(VI) porphyrin (PEG-2), which could react with hydrocarbons to give oxidation products in up to 80 % yield. The behavior of the two PEG-supported ruthenium porphyrin complexes in water was probed by NMR spectroscopy and dynamic light-scattering measurements. PEG-2 is remarkably stable to water. The secondorder rate constants (k2) for the oxidation of styrene and ethylbenzene by PEG-2 in dioxane-water increase with water content, and the k2 values at a water content of 70% or 80% are up to 188 times that obtained in ClCH2CH2Cl. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.