Manganese complexes with acyclic compartmental Schiff bases

The end-off acyclic compartmental ligands H 5-L A and H 6-L B have been prepared by [2 + 1] or [3 + 1] condensation of the appropriate amounts of pyridoxal hydrochloride with 1,3-diamine-2-propanol and 3-formylsalicylic acid with tris-2-(aminoethyl)amine, respectively. The ligand H 5-L A, which contains two adjacent N 2O chambers, bears an endogenous hydroxo potentially bridging group and H 6-L B, which contains an inner N 4O 3 and an outer O 3O 3 compartment, bears three potentially bridging phenolic groups. The complexes [Mn 2(H 2-L A)(CH 3COO) 2](Cl) o5H 2O and [Mn(H 3-L B)]o0.25H 2OoCH 3OH have been obtained by the template condensation of the appropriate amine and formyl precursors in the presence of Mn(CH 3COO) 2o4H 2O in methanol. When recrystallized [Mn 2(H 2-L A)(CH 3COO) 2](Cl)o5H 2O undergoes demetalation reaction giving rise to [Mn(H 3-L A)(H 2O) 2](Cl)(H 2O) where the octahedral manganese(III) ion is surrounded by two axial water molecules trans with respect to the equatorial plane formed by the two imine nitrogen atoms and the two phenolate oxygen atoms of the Schiff base [H 3-L A] 2-. The central -OH group of [H 3-L A] 2-does not participate in the coordination. In [Mn(H 3-L B)]o0.25H 2OoCH 3OH the octahedral environment about the manganese(III) ion is reached by the coordination of three carboxylate and three phenolate oxygen atoms of the external O 3O 3 site and the three imine nitrogen atoms are protonated.