Issue 30, 2015

Bimetallic MnIII–FeII hybrid complexes formed by a functionalized MnIII Anderson polyoxometalate coordinated to FeII: observation of a field-induced slow relaxation of magnetization in the MnIII centres and a photoinduced spin-crossover in the FeII centres

Abstract

The synthesis and crystal structure of an Anderson POM functionalized with two 2,6-di(pyrazol-1-yl)-pyridine (1-bpp) ligands are reported (compound 1). High-frequency electron paramagnetic resonance (HF-EPR) and magnetic measurements show that it presents a significant negative axial zero-field splitting and field-induced slow relaxation of magnetization due to the presence of isolated MnIII anisotropic magnetic ions. Complexation of 1 with FeII gives rise to a 2D cationic network formed by Anderson POMs coordinated to two FeII ions through the two tridentate 1-bpp ligands and to other two FeII ions through two oxo ligands in compound 2, and to an anionic polymeric network formed by Anderson POMs coordinated through the 1-bpp ligands to two FeII, which are coordinated to two 1-bpp ligands from two neighbouring POMs, in compound 3. The crystal structure of 2 has been solved. Magnetic properties show that the FeII atoms of 3 remain in the low-spin state, while those of 2 remain in the high-spin state due to coordination to oxygen atoms from a neighbouring POM and dimethylformamide and water solvent molecules. Irradiation of 3 at 10 K with green light induces a spin-crossover (LIESST effect) with a small but significant photoconversion (∼8%). Finally, AC susceptibility measurements of 2, 3 and (C16H36N)3[MnMo6O18{(OCH2)3CNH2}2] (4) confirm field-induced slow relaxation of magnetization of MnIII Anderson POMs.

Graphical abstract: Bimetallic MnIII–FeII hybrid complexes formed by a functionalized MnIII Anderson polyoxometalate coordinated to FeII: observation of a field-induced slow relaxation of magnetization in the MnIII centres and a photoinduced spin-crossover in the FeII centres

Supplementary files

Article information

Article type
Paper
Submitted
17 avr. 2015
Accepted
26 mai 2015
First published
27 mai 2015
This article is Open Access
Creative Commons BY license

J. Mater. Chem. C, 2015,3, 7936-7945

Author version available

Bimetallic MnIII–FeII hybrid complexes formed by a functionalized MnIII Anderson polyoxometalate coordinated to FeII: observation of a field-induced slow relaxation of magnetization in the MnIII centres and a photoinduced spin-crossover in the FeII centres

A. Abhervé, M. Palacios-Corella, J. M. Clemente-Juan, R. Marx, P. Neugebauer, J. van Slageren, M. Clemente-León and E. Coronado, J. Mater. Chem. C, 2015, 3, 7936 DOI: 10.1039/C5TC01089F

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