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Article Dans Une Revue Journal of the American Chemical Society Année : 2013

Stimuli responsive hybrid magnets : tuning the photoinduced spin-crossover in Fe(III) complexes inserted into layered magnets

Résumé

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.

Domaines

Matériaux
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Dates et versions

hal-00840683 , version 1 (02-07-2013)

Identifiants

Citer

Miguel Clemente-León, Eugenio Coronado, Maurici López-Jordà, João C. Waerenborgh, Cédric Desplanches, et al.. Stimuli responsive hybrid magnets : tuning the photoinduced spin-crossover in Fe(III) complexes inserted into layered magnets. Journal of the American Chemical Society, 2013, 135 (23), pp.8655-8667. ⟨10.1021/ja402674x⟩. ⟨hal-00840683⟩
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