Synthesis and structural characterisation of new manganese(II) and (III) complexes.: Study of their photolytic and catalase activity and X-ray crystal structure of [Mn(3-OMe, 5-Br-salpn) (EtOH) (H2O)]ClO4

New [(MnL)-L-II(H2O)(2)] and [(MnL)-L-III(H2O)(2)]ClO4 complexes, where L are substituted N,N'-bis(salicylidene)propane-1,3-diamine (H(2)salpn) ligands have been prepared and thoroughly characterised by elemental analysis, IR and mass spectroscopy, conductivity and magnetic measurements at room temperature (and, in the case of 1, at variable temperature). Cyclic and normal pulse voltammetry measurements were also performed. All these studies support an octahedral geometry around the metal with the Schiff base in the equatorial plane acting as tetradentate and solvent molecules in the axial positions. Crystallographic characterisation of 6 confirms this geometry and shows a supramolecular structure involving pi-pi stacking and hydrogen bonding interactions. The ability to split water by these complexes and their catalase activity has also been studied. (C) 2000 Elsevier Science Ltd All rights reserved.