Synthesis and structural characterisation of new manganese(II) and (III) complexes. Study of their photolytic and catalase activity and X-ray crystalstructure 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 a re substituted N,N'-bis(salicylidene)propane-1,3-diamine (H(2)salpn) ligand s have been prepared and thoroughly characterised by elemental analysis, IR and mass spectroscopy, conductivity and magnetic measurements at room temp erature (and, in the case of 1, at variable temperature). Cyclic and normal pulse voltammetry measurements were also performed. All these studies supp ort an octahedral geometry around the metal with the Schiff base in the equ atorial plane acting as tetradentate and solvent molecules in the axial pos itions. Crystallographic characterisation of 6 confirms this geometry and s hows a supramolecular structure involving pi-pi stacking and hydrogen bondi ng interactions. The ability to split water by these complexes and their ca talase activity has also been studied. (C) 2000 Elsevier Science Ltd All ri ghts reserved.