Studies of the binding modes of carboxylate donors with manganese(III) complexes containing tetradentate Schiff base ligands.: Crystal structures of the complexes [Mn(3-CH3Osalpn)(HO2CC6H4CO2)]n and [{Mn(5-NO2salpn)(OH)(H2O)} {Mn(5-NO2salpn)-(HO2CC6H4CO2)(H2O)}]•C2H5OH

Manganese(III) complexes of stoichiometry MnL(HO2CRCO2)(H2O)(n) (L = 3-CH(3)Osalpn, 3,5-CH(3)Osalpn, 5-NO(2)salpn, 3-Br, 5-NO(2)salpn; R = o-C6H4, CH2, C2H4, C3H6 and n = 0-3) have been synthesised. The compounds have been characterised by elemental analyses, IR spectroscopy, fast atom bombardment mass spectrometry (FAB) and magnetic susceptibility measurements. The X-ray structure of [Mn(3-CH(3)Osalpn)(HO2CC6H4CO2)](n) (1) has been determined. The hydrogenphthalate ligands link the manganese centres into polymeric chains. Slow evaporation of an ethanol solution of [Mn(5-NO(2)salpn)(HO2CC6H4CO2)(H2O)] yielded [{Mn(5-NO(2)salpn)(OH)(H2O)}{Mn(5-NO(2)salpn)(HO2CC6H4CO2)(H2O)}]. C2H5OH (2), also crystallographically characterised. The two cocrystallised Mn(III) complexes an monomeric, with a distorted octahedral geometry, and they interact by hydrogen bond and pi-pi stacking. In both 1 and 2, the hydrogenphthalate ligand is monoanionic, however, the coordination mode of this carboxylate is found to differ, showing the versatility of carboxylates as ligands. (C) 1999 Elsevier Science S.A. All rights reserved.