ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P50. Effect of the Rhombicity on the Peroxidase Activity of Manganese(III)
Complexes with Schiff Bases and Ambidentade Ligands
I.M. Fernandez-Garcia a , A. Vazquez-Fernandez a , M.J. Rodríguez-Doutón a , M. Maneiro a ,
A.M. González-Noya b , M.R. Bermejo b
a
Quimica Inorganica, Universidad de Santiago de Compostela, Facultad de, Alfonso x, 27002, Lugo, Spain
e-mail: isaferga@lugo.usc.es
b
Quimica Inorganica, Universidad de Santiago de Compostela, Facultad de, Avda Ciencias, 15006, Santiago
Compostela, Spain
In the past few decades manganese chemistry has attracted much attention because of its role as an important
cofactor of several electron-transfer metalloproteins. For example, the manganese peroxidases (MnP) catalyse
the oxidation of a wide variety of substrates by H2O2.
Recently, we have tried to establish a correlation between the peroxidase activity and the structural motifs of the
complexes [1]. As an extension of our investigation on this catalytic behaviour, we have prepared and studied
new Mn(III) complexes, derived from five Schiff bases and one ambidentade ligand (NCS - ). In these complexes
the metal centre exhibits an octahedral environment, with the N2O2 donor set of the ligand bound to the Mn(III)
ion in the equatorial plane and one molecule of solvent and other of NCS - along the symmetry axis. This solvent
axial molecule constitutes a quite labile ligand, which could generate a vacant position in the coordination sphere
to accommodate a substrate. In order to quantify the tetragonal elongation we have employed the "rhombicity" of
the structures as the ratio between the manganese-axial-oxygen distances and the manganese-equatorial-oxygen
distances. Peroxidase activity was expressed as ratio between ABTS •+ absorbance and manganese complexes
absorbance at 415 nm. The peroxidase activity of these Mn(III) complexes versus the rhombicity is shown in
figure 1.
References:
[1] M. R. Bermejo, M. I. Fernández, A. M. González-Noya, M. Maneiro, R. Pedrido, M. J. Rodriguez, J. C.
Monteagudo, B. Donnadieu; J. Inorg. Biochem., 100, 1470 (2006).
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