Manganese(III) complexes with tetradentate salicylaldimine Schiff bases: Synthesis, structure, self assembly and catalase activity

Three new mononuclear manganese(III) complexes [Mn(L1)(SeCN)(DMSO)] (1), [Mn(L2)(N3)(DMSO)] (2) and [Mn(L3)(CH3OH)2]ClO4 (3) [where H2L1 = N,N′-bis((2-hydroxy-1-naphthyl)methylidene)phenyl-1,2-diamine, H2L2 = N,N′-bis((2-hydroxy-1-naphthyl)methylidene)-2,2-dimethylpropane-1,3-diamine and H2L3 = N,N′-bis(1-(1′-hydroxy-2-naphthyl)ethylidene)propane-1,3-diamine] have been prepared and characterized by elemental and spectral analysis and single crystal X-ray diffraction studies. Complexes 1 and 2 show six-coordinate distorted octahedral geometry around the manganese(III) center and are bonded to the respective deprotonated tetradentate ligands together with a monodentate pseudohalide. The sixth coordination site is occupied by solvent DMSO molecule. Complex 3 is also octahedral, but it is bonded to a deprotonated tetradentate ligand and two solvent methanol molecules. Complex 3 is distinctive in the sense that it catalyzes the disproportionation of hydrogen peroxide into water and dioxygen i.e. it possesses catalase activity. The catalase activity of complex 3 may be related with its structure. Supramolecular interactions in all three complexes were explored.

Graphical abstractThree new mononuclear manganese(III) complexes with three similar tetradentate Schiff base ligands have been synthesized and characterized. One of the complexes shows catalase activity.Figure optionsDownload full-size imageDownload as PowerPoint slide