THE DIVERSITY OBSERVED IN MANGANESE(III) COMPLEXES OF TETRADENTATE SCHIFF-BASE LIGANDS - AN ASSESSMENT OF STRUCTURAL TRENDS

A series of manganese(III) complexes of aryl substituted N2O2 donor se t Schiff base ligands has been prepared by the aerial oxidation of man ganese(II) precursors. The resultant complexes of stoichiometry [MnL]C lO4 . nH(2)O (where n = 1-3) have been thoroughly characterised by ele mental analyses, infrared spectroscopy, fast atom bombardment (FAB) ma ss spectrometry, magnetic susceptibility measurements and paramagnetic H-1 NMR. The crystal structure of [MnL(7)(H2O)(2)]ClO4 ., H2O 1, show s it to consist of a polymeric array of roughly octahedral [MnL(7)(H2O )(2)](+) cations linked cin an intricate network of hydrogen bonds bet ween the perchlorate counterion and the lattice water molecule. This h ydrogen bonding is further enhanced by pi-pi stabilisation between the aryl rings of the Schiff base ligands. An attempt is made to rational ise the structural chemistry observed by us for complexes of this type . Copyright (C) 1996 Elsevier Science Ltd