A Ferromagnetic Methoxido-Bridged Mn(III) Dimer and a Spin-Canted Metamagnetic μ1,3-Azido-Bridged Chain

Two new Mn(III) complexes of formulas [MnL1(N3)(OMe)]2 (1) and [MnL2(N3)2]n (2) have been synthesized by using two tridentate NNO-donor Schiff base ligands HL1{(2-[(3-methylaminoethylimino)-methyl]-phenol)} and HL2 {(2-[1-(2-dimethylaminoethylimino)methyl]phenol)}, respectively. Substitution of the H atom on the secondary amine group of the N-methyldiamine fragment of the Schiff base by a methyl group leads to a drastic structural change from a methoxido-bridged dimer (1) to a single μ1,3-azido-bridged 1D helical polymer (2). Both complexes were characterized by single-crystal X-ray structural analyses and variable-temperature magnetic susceptibility measurements. The magnetic properties of compound 1 show the presence of weak ferromagnetic exchange interactions mediated by double methoxido bridges (J = 0.95 cm–1). Compound 2 shows the existence of a weak antiferromangetic coupling along the chain (J = −8.5 cm–1) through the single μ1,3-N3 bridge with a spin canting that leads to a long-range antiferromag...