Formation of Novel 1‐D Chains by μ‐Amido Bridging of Dinuclear Manganese(III)‐Schiff Base Complexes

Three novel neutral manganese( III ) complexes of stoichiometry Mn(R‐amsal‐3,5‐di‐ t Bu)(H 2 O) n [H 3 ‐R‐amsal‐3,5‐di‐ t Bu = 3‐aza‐4‐(2‐hydroxyphenyl)‐ N ‐(2‐hydroxyphenyl)but‐3‐enamide; (R = H, 4‐Me, 5‐ t Bu)] have been synthesised using potentially trianionic and pentadentate Schiff‐base ligands containing an amide group. Complexes were thoroughly characterised by elemental analysis, FAB mass spectrometry, infrared spectroscopy, magnetic susceptibility measurements and molar conductivities. Recrystallisation of these complexes from methanol yielded single crystals of [Mn 2 (amsal‐3,5‐di‐ t Bu) 2 (MeOH) 2 ] n 1 , [Mn 2 (4‐Me‐amsal‐3,5‐di‐ t Bu) 2 (MeOH) 2 ] n 2 and [Mn 2 (5‐ t Bu‐amsal‐3,5‐di‐ t Bu) 2 (MeOH) 2 ] n 3 with methanol as solvate. Their X‐ray characterisation shows that these complexes consist of infinite one‐dimensional chains with a repeating cyclic dimeric unit, where the amide oxygen atom is bridging two neighbouring manganese( III ) ions. Paramagnetic 1 H NMR spectroscopy confirmed the presence of Mn III in these complexes, while the cyclic voltammetry studies suggest the possibility of obtaining polynuclear Mn IV complexes with this kind of ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)