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A Ferromagnetic Methoxido-Bridged Mn(III) Dimer and a Spin-Canted Metamagnetic μ<sub>1,3</sub>-Azido-Bridged Chain

By Subrata Naiya (2086702), Saptarshi Biswas (1839817), Michael G. B. Drew (1637032), Carlos J. Gómez-García (1647151) and Ashutosh Ghosh (1518748)

Abstract

Two new Mn­(III) complexes of formulas [MnL<sup>1</sup>(N<sub>3</sub>)­(OMe)]<sub>2</sub> (<b>1</b>) and [MnL<sup>2</sup>(N<sub>3</sub>)<sub>2</sub>]<sub><i>n</i></sub> (<b>2</b>) have been synthesized by using two tridentate NNO-donor Schiff base ligands HL<sup>1</sup>{(2-[(3-methylaminoethylimino)-methyl]-phenol)} and HL<sup>2</sup> {(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 (<b>1</b>) to a single μ<sub>1,3</sub>-azido-bridged 1D helical polymer (<b>2</b>). Both complexes were characterized by single-crystal X-ray structural analyses and variable-temperature magnetic susceptibility measurements. The magnetic properties of compound <b>1</b> show the presence of weak ferromagnetic exchange interactions mediated by double methoxido bridges (<i>J</i> = 0.95 cm<sup>–1</sup>). Compound <b>2</b> shows the existence of a weak antiferromangetic coupling along the chain (<i>J</i> = −8.5 cm<sup>–1</sup>) through the single μ<sub>1,3</sub>-N<sub>3</sub> bridge with a spin canting that leads to a long-range antiferromagnetic order at <i>T</i><sub>c</sub> ≈ 9.3 K and a canting leading to a weak ferromagnetic long-range order at <i>T</i><sub>c</sub> ≈ 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

Topics: Biophysics, Biochemistry, Medicine, Biotechnology, Plant Biology, Chemical Sciences not elsewhere classified, Physical Sciences not elsewhere classified, methoxido bridges, H atom, ligand, presence, Substitution, exibits metamagnetic behavior, fragment, Schiff base, compound 1 show, antiferromangetic, Dimer, dimethylaminoethylimino, amine group, dimer, .1.2 T, methyl group, HL, formula, exchange interactions, Mn, MnL, analyses, cm, helical, Metamagnetic, 8.5, 9.3, antiferromagnetic interchain interactions, antiferromagnetic order, 0.95, polymer, Tc, tridentate, complex, susceptibility measurements, Ferromagnetic, phase, ChainTwo
Year: 2012
DOI identifier: 10.1021/ic300274n.s001
OAI identifier: oai:figshare.com:article/2524951
Provided by: FigShare
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