Dimanganese(II) complexes of a new phenol-based dinucleating ligand with two amino chelating arms: Synthesis, structure and catalase-like activity

A new phenol-based dinucleating ligand with two amino chelating arms, 2,6-bis{[N-(2-dimethylaminoethyl)-N-methyl] aminomethyl}-4-methylphenolate (L-), formed dinuclear manganese(ii) complexes [Mn2L(p-XC6H4CO2)(2)(NCS) (MeOH)] (X = H 1, CI 2, Me 3 or NO2 4). X-Ray analysis revealed that complex 1 crystallizes in the monoclinic space group P2(1)/c. a = 12.607(3), b = 19.566(6), c = 16.743(5) Angstrom and beta = 107.56(2)degrees. The two manganese ions are bridged by the phenolic oxygen and two benzoate groups. The NCS- ion is co-ordinated to one of the manganese ions through its nitrogen and the methanol molecule to the other. providing distorted-octahedral geometries around each manganese. Magnetic susceptibility measurements over the temperature ii range 4.2-300 K indicated a weak antiferromagnetic interaction (J = -3 to -5 cm(-1) based on (H) over cap = -2J (S) over cap(1) .(S) over cap(2)). The complexes show a catalase-like activity in disproportionating H2O2 in dimethylformamide. The rate of dioxygen evolution was proportional to the concentration of H2O2 and the rate constant decreased in the order 1 (X = H) > 2(CI) > 3(Me) > 4(NO2).