title: A ferromagnetic methoxido-bridged Mn(III) dimer and a spin-canted metamagnetic μ(1,3)-azido-bridged chain.
abstract: Two new Mn(III) complexes of formulas [MnL(1)(N(3))(OMe)](2) (1) and [MnL(2)(N(3))(2)](n) (2) have been synthesized by using two tridentate NNO-donor Schiff base ligands HL(1){(2-[(3-methylaminoethylimino)-methyl]-phenol)} and HL(2) {(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 μ(1,3)-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 μ(1,3)-N(3) bridge with a spin canting that leads to a long-range antiferromagnetic order at T(c) ≈ 9.3 K and a canting leading to a weak ferromagnetic long-range order at T(c) ≈ 8.5 K. It also exibits metamagnetic behavior at low temperatures with a critical field of ca.1.2 T due to the weak antiferromagnetic interchain interactions that appear in the canted ordered phase.
authors.affiliation: Department of Chemistry, University College of Science, University of Calcutta, 92, APC Road, Kolkata 700 009, India.
authors.forename: Subrata
authors.initials: S
authors.lastname: Naiya
authors.forename: Saptarshi
authors.initials: S
authors.lastname: Biswas
authors.forename: Michael G B
authors.initials: MG
authors.lastname: Drew
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: Gómez-García
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Ghosh