1. Synthesis, Characterization, and Catalytic Studies of Mn(III)-Schiff Base-Dicyanamide Complexes: Checking the Rhombicity Effect in Peroxidase Studies.
- Author
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Bermejo, Manuel R., Carballido, Rocío, Fernández-García, M. Isabel, González-Noya, Ana M., González-Riopedre, Gustavo, Maneiro, Marcelino, and Rodríguez-Silva, Laura
- Subjects
MANGANESE compounds ,CHEMICAL synthesis ,CATALYTIC activity ,SCHIFF bases ,PEROXIDASE ,METAL complexes ,NUCLEAR magnetic resonance spectroscopy - Abstract
The condensation of 3-methoxy-2-hydroxybenzaldehyde and the diamines 1,2-diphenylendiamine, 1,2-diamine-2-methylpropane and 1,3-propanediamine yielded the dianionic tetradentate Schiff base ligands N,N′-bis(2-hydroxy-4-methoxybenzylidene)-1,2-diphenylendiimine (H
2 L1 ), N,N′-bis(2-hydroxy-4-methoxybenzylidene)-1,2-diamino-2-methylpropane (H2 L2 ) and N,N′-bis(2-hydroxy-4-methoxybenzylidene)-1,3-diaminopropane (H2 L3 ) respectively. The organic compounds H2 L1 and H2 L2 have been characterized by elemental analysis, IR,1 H and13 C NMR spectroscopies and mass spectrometry electrospray (ES). The crystal structure of H2 L2 in solid state, solved by X-ray crystallography, is highly conditioned in the solid state by two N-H•••N intramolecular interactions. The synthesis of three new manganese(III) complexes 1–3, incorporating these ligands, H2 L1 –H2 L3 , and dicyanamide (DCA), is reported. The complexes 1–3 have been physicochemically characterized by elemental analysis, IR and paramagnetic1 H NMR spectroscopy, ESI mass spectrometry, magnetic moment at room temperature and conductivity measurements. Complex 1 has been crystallographically characterized. The X-ray structure shows the self-assembly of the Mn(III)-Schiff base-DCA complex through µ-aquo bridges between neighbouring axial water molecules and also by π-π stacking interactions, establishing a dimeric structure. The manganese complexes were also tested as peroxidase mimics for the H2 O2 -mediated reaction with the water-soluble trap ABTS, showing complexes 1-2 relevant peroxidase activity in contrast with 3. The rhombicity around the metal ion can explain this catalytic behaviour. [ABSTRACT FROM AUTHOR]- Published
- 2017
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