Synthesis, characterization and catalase activity of a water soluble diMnIII complex of a sulphonato-substituted Schiff base ligand: An efficient catalyst for H2O2 disproportionation

PALOPOLI, C.; BRUZZO, N.; HUREAU, C; LADEIRA, S.; MURGIDA, D.; SIGNORELLA, S.

INORGANIC CHEMISTRY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2011 vol. 50 p. 8973 - 8983

0020-1669

A new diMnIII complex, Na[Mn2(3-Me-5-SO3-salpentO)(μ-MeO)(μ- AcO)(H2O)] 3 4H2O (1), where salpentOH = 1,5-bis(salicylidenamino) pentan-3-ol, was synthesized and structurally characterized. The complex possesses a bis(μ-alkoxo)(μ-acetato) triply bridged diMnIII core, the structure of which is retained upon dissolution. Complex 1 is highly efficient to disproportionate H2O2 in an aqueous solution of pH g 8.5 or in DMF, with only a slight decrease of activity. Electrospray ionization mass spectrometry, EPR, and UVvis spectroscopy used to monitor the H2O2 disproportionation in buffered basic medium, suggest that the major active form of the catalyst during cycling occurs in the MnIII2 oxidation state and that the starting complex retains the dinuclearity and composition during catalysis, with the acetate that moves from bridging to terminal ligand.