III International Conference

PP-III-90KINETIC AND THERMODYNAMIC STUDIES OF CATALASE-LIKE ACTIVITYOF THE ONE DIMENSIONAL MANGANESE COORDINATION POLYMER FORHYDROGEN PEROXIDE DISPROPORTIONATIONİbrahim Kani, Canan Darak, Onur Şahin 1 , Orhan Büyükgüngör 1Department of Chemistry, Anadolu University 26470, Eskişehir, Turkey1 Department of Physics, Ondokuz Mayis University, TR-55139, Samsun, TurkeyE-mail : ibrahimkani@anadolu.edu.trPolymeric complex [Mn(O 2 C(CF 2 ) 8 CO 2 )(phen) 2 ] n H 2 O synthesis and full characterizationhas been done with physical methods. Crytallographic data show that each Mn(II) ion isoctahedrally coordinated by two bidentate phenantroline ligands and the carboxylate oxygenatoms from two symmetry related perflourosebacate ligands which are coordinated in a cisoidposition. The structure consists of polymeric chains, with the perfluorosebacate ligandsbridging the Mn(II) ions in a monodentate fashion. The complex catalyzes thedisproportination of hydrogen peroxide into water and dioxygen and it does not exhibitsaturation kinetics with substrate. No induction period was needed before vigorous evolutionof dioxygen occurred in methanol. The initial reaction rates and their temperature and basedependencies were investigated by monitoring the dioxygen evolution. These kinetic studiessupport the experimental rate law as rate = k [catalyst] [H 2 O 2 ] in the range of concentrationstudied: -lnv o = 1.41 ln[catalyst] – 1.231; -lnv o = 0.839 ln[H 2 O 2 ] – 7.544. Activationparameters have been calculated at 301 K: E a = 50.0 kJ mol -1 ; ΔH ‡ = 47.5 kJ mol -1 ;ΔS ‡ = -153.8 J K -1 mol -1 ; ΔG ‡ = 96.3 J K -1 mol -1 . UV-vis spectroscopy was used to monitorthe reaction catalyzed by manganese complex.160140120O2 evolved (ml)1008060402000 50 100 150 Time 200 (min.) 250 300 350 400methanol ( ),acetonitrile (◊), DMF (Ο), water (Δ)Conditions; [catalyst] = 0.886 M [H 2 O 2 ] = 4.850M at 295 K.639