Halogen substitution effects on N2O schiff base ligands in unprecedented abrupt Fe(II) spin crossover complexes - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Chemistry - A European Journal Année : 2017

Halogen substitution effects on N2O schiff base ligands in unprecedented abrupt Fe(II) spin crossover complexes

Résumé

A family of halogen-substituted Schiff base iron(II) complexes, [Fe(II) (qsal-X)2 ], (qsal-X=5-X-N-(8-quinolyl)salicylaldimines)) in which X=F (1), Cl (2), Br (3) or I (4) has been investigated in detail. Compound 1 shows a temperature invariant high spin state, whereas the others all show abrupt spin transitions, at or above room temperature, namely, 295 K (X=I) up to 342 K (X=Br), these being some of the highest T1/2 values obtained, to date, for Fe(II) N/O species. We have recently reported subtle symmetry breaking in [Fe(II) (qsal-Cl)2 ] 2 with two spin transition steps occurring at 308 and 316 K. A photomagnetic study reveals almost full HS conversion of [Fe(II) (qsal-I)2 ] 4 at low temperature (T(LIESST)=54 °K). The halogen substitution effects on the magnetic properties, as well as the crystal packing of the [Fe(II) (qsal-X)2 ] compounds and theoretical calculations, are discussed in depth, giving important knowledge for the design of new spin crossover materials. In comparison to the well known iron(III) analogues, [Fe(III) (qsal-X)2 ](+) , the two extra π-π and P4AE interactions found in [Fe(II) (qsal-X)2 ] compounds, are believed to be accountable for the spin transitions occurring at ambient temperatures.

Dates et versions

hal-01537646 , version 1 (12-06-2017)

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Citer

Wasinee Phonsri, David S. Macedo, Kuduva R. Vignesh, Gopalan Rajaraman, Casey G. Davies, et al.. Halogen substitution effects on N2O schiff base ligands in unprecedented abrupt Fe(II) spin crossover complexes. Chemistry - A European Journal, 2017, 23 (29), pp.7052-7065. ⟨10.1002/chem.201700232⟩. ⟨hal-01537646⟩
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