Degradation of polyfluorinated aromatics : A novel efficient oxidative method using N-bridged diiron complex

C. Colomban (1) , E. Kudrik (1) , P. Afanasiev (1) , A. Sorokin (1)

1 BIOVERT - BIOVERT

Highly halogenated aromatics are among the most recalcitrant priority pollutants. The large scale production and application of fluorinated xenobiotics coupled with their inertness leads to their accumulation in the environment thus posing severe problems. Disposal of these compounds resistant to biodegradation is of crucial importance for preserving the environment. Much research has been dedicated to the development of systems able to perform catalytic hydrodefluorination of fluorocarbons. Current approaches are mainly based on reductive C-F activation and are limited by low turnover numbers and strictly anaerobic and dry conditions. [1] We develop novel bio-inspired diiron catalysts who display two iron atoms bridged by ľ-nitrido group and stabilized by macrocyclic supporting ligands. [2] In particular, N-bridged diiron tetra-tert-butylphthalocyanine, (FePctBu4)2N, can activate H2O2 for the most challenging oxidations, e.g. oxidation of methane. [3] We show here a further development of this system for dehalogenation and oxidative degradation of harmful polyfluorinated aromatics. The (FePctBu4)2N - H2O2 system performs the oxidative degradation of perfluoroaromatics under air in both organic or water solvents. This tolerance to air and water is of exceptional importance since other approaches to defluorination often need very strict conditions. The process is highly efficient with a large scope of fluorinated aromatic substrates. Catalytic properties of (FePctBu4)2N-H2O2 will be presented and mechanistic features will be discussed. [1] C. Douvris, O. V. Ozerov, Science, 2008, 321, 1188-1190 [2] E. V. Kudrik, P. Afanasiev, L. X. Alvarez, P. Dubourdeaux, M. Clémancey, J. M. Latour, G. Blondin, D. Bouchu, F. Albrieux, S. E. Nededov, A. B. Sorokin, Nature Chem, 2012, 4, 1024-1029 [3] a) A.B. Sorokin, E. Kudrik, D. Bouchu, Chem.Comm., 2008, 2562-2564 b) P. Afanasiev E. V. Kudrik, J. M. Millet, D. Bouchu, A. B. Sorokin, Dalton Trans., 2011, 40, 701-710

Domaines: Catalyse; Environnement et Société

C. Colomban, E. Kudrik, P. Afanasiev, A. Sorokin. Degradation of polyfluorinated aromatics : A novel efficient oxidative method using N-bridged diiron complex. Gecom Concoord, May 2013, Cap d'Agde, France. ⟨hal-00824174⟩