Stimuli responsive hybrid magnets : tuning the photoinduced spin-crossover in Fe(III) complexes inserted into layered magnets
Language
en
Article de revue
This item was published in
Journal of the American Chemical Society. 2013-06-12, vol. 135, n° 23, p. 8655-8667
American Chemical Society
English Abstract
The insertion of a [Fe(sal2-trien)](+) complex cation into a 2D oxalate network in the presence of different solvents results in a family of hybrid magnets with coexistence of magnetic ordering and photoinduced spin-crossover ...Read more >
The insertion of a [Fe(sal2-trien)](+) complex cation into a 2D oxalate network in the presence of different solvents results in a family of hybrid magnets with coexistence of magnetic ordering and photoinduced spin-crossover (LIESST effect) in compounds [Fe(III)(sal2-trien)][Mn(II)Cr(III)(ox)3]*CHCl3 (1*CHCl3), [Fe(III)(sal2-trien)][Mn(II)Cr(III)(ox)3]*CHBr3 (1*CHBr3), and [Fe(III)(sal2-trien)][Mn(II)Cr(III)(ox)3]*CH2Br2 (1*CH2Br2). The three compounds crystallize in a 2D honeycomb anionic layer formed by Mn(II) and Cr(III) ions linked through oxalate ligands and a layer of [Fe(sal2-trien)](+) complexes and solvent molecules (CHCl3, CHBr3, or CH2Br2) intercalated between the 2D oxalate network. The magnetic properties and Mössbauer spectroscopy indicate that they undergo long-range ferromagnetic ordering at 5.6 K and a spin crossover of the intercalated [Fe(sal2-trien)](+) complexes at different temperatures T1/2. The three compounds present a LIESST effect with a relaxation temperature TLIESST inversely proportional to T1/2. The isostructural paramagnetic compound, [Fe(III)(sal2-trien)][Zn(II)Cr(III)(ox)3]*CH2Cl2 (2*CH2Cl2) was also prepared. This compound presents a partial spin crossover of the inserted Fe(III) complex as well as a LIESST effect. Finally, spectroscopic characterization of the Fe(III) doped compound [Ga0.99Fe0.01(sal2trien)][Mn(II)Cr(III)(ox)3]*CH2Cl2 (3*CH2Cl2) shows a gradual and complete thermal spin crossover and a LIESST effect on the isolated Fe(III) complexes. This result confirms that cooperativity is not a necessary condition to observe the LIESST effect in an Fe(III) compound.Read less <
English Keywords
Complex cation
Oxalate network
Solvents
Hybrid magnets
Magnetism
Fe(III)
Origin
Hal imported