Azide-bridged one-dimensional MnIII polymers:: Effects of side group of Schiff base ligands on structure and magnetism

By changing ancillary tetradentate Schiff base ligands (L), two new one-dimensional azide-bridged manganese(III) coordination complexes [Mn-III(L)(mu(1,3)-N-3)](n) [L = 5-Fsalen (1), 5-OCH3 (2); salen = N,N'-bis(salicylidene)-1,2diaminoethane] as well as a mononuclear complex [Mn-III(salophen)(N-3)] (3) [salophen = N,N'-bis(salicylidene)-o-phenylenediamine] have been successfully obtained. All of them have been structurally and magnetically characterized. In the structures of 1-3 each Mn-III ion is in a distorted octahedral geometry with an obvious Jahn-Teller effect, where the tetradentate L ligands all bind in the equatorial mode, whereas in the axial direction, the N3- ion acts as an end-to-end bridge in 1 and 2 while a terminal group in 3 with a methanol molecule at the other end. Magnetic characterization shows that the mu(1,3)-b ridging azide ion proves to mainly transmit antiferromagnetic interaction between Mn-III ions, but these three complexes exhibit various magnetic behaviors at low temperatures. Noteworthily, complex 2 behaves as a weak ferromagnet with a relatively large coercive field of 2.3 kOe, much larger than the value reported previously.