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

(T)hree new mononuclear manganese(III) complexes [Mn(L-1)(SeCN)(DMSO)] (1), [Mn(L-2)(N-3)(DMSO)] (2) and [Mn(L-3)(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-naphthypethylidene)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. (C) 2016 Elsevier Ltd. All rights reserved.