title: Nonanuclear Spin-Crossover Complex Containing Iron(II) and Iron(III) Based on a 2,6-Bis(pyrazol-1-yl)pyridine Ligand Functionalized with a Carboxylate Group.
abstract: The synthesis and magnetostructural characterization of [Fe(III)3(μ3-O)(H2O)3[Fe(II)(bppCOOH)(bppCOO)]6](ClO4)13·(CH3)2CO)6·(solvate) (2) are reported. This compound is obtained as a secondary product during synthesis of the mononuclear complex [Fe(II)(bppCOOH)2](ClO4)2 (1). The single-crystal X-ray diffraction structure of 2 shows that it contains the nonanuclear cluster of the formula [Fe(III)3(μ3-O)(H2O)3[Fe(II)(bppCOOH)(bppCOO)]6](13+), which is formed by a central Fe(III)3O core coordinated to six partially deprotonated [Fe(II)(bppCOOH)(bppCOO)](+) complexes. Raman spectroscopy studies on single crystals of 1 and 2 have been performed to elucidate the spin and oxidation states of iron in 2. These studies and magnetic characterization indicate that most of the iron(II) complexes of 2 remain in the low-spin (LS) state and present a gradual and incomplete spin crossover above 300 K. On the other hand, the Fe(III) trimer shows the expected antiferromagnetic behavior. From the structural point of view, 2 represents the first example in which bppCOO(-) acts as a bridging ligand, thus forming a polynuclear magnetic complex.
authors: Instituto de Ciencia Molecular (ICMol), Universidad de Valencia , Catedrático José Beltrán 2, 46980 Paterna, Spain.
authors: Alexandre
authors: A
authors: Abhervé
authors: Instituto de Ciencia Molecular (ICMol), Universidad de Valencia , Catedrático José Beltrán 2, 46980 Paterna, Spain.
authors: María José
authors: MJ
authors: Recio-Carretero
authors: Instituto de Ciencia Molecular (ICMol), Universidad de Valencia , Catedrático José Beltrán 2, 46980 Paterna, Spain.
authors: Maurici
authors: M
authors: López-Jordà
authors: Instituto de Ciencia Molecular (ICMol), Universidad de Valencia , Catedrático José Beltrán 2, 46980 Paterna, Spain.
authors: Juan Modesto
authors: JM
authors: Clemente-Juan
authors: Instituto de Ciencia Molecular (ICMol), Universidad de Valencia , Catedrático José Beltrán 2, 46980 Paterna, Spain.
authors: Josep
authors: J
authors: Canet-Ferrer
authors: Instituto de Ciencia Molecular (ICMol), Universidad de Valencia , Catedrático José Beltrán 2, 46980 Paterna, Spain.
authors: Andrés
authors: A
authors: Cantarero
authors: Instituto de Ciencia Molecular (ICMol), Universidad de Valencia , Catedrático José Beltrán 2, 46980 Paterna, Spain.
authors: Miguel
authors: M
authors: Clemente-León
authors: Instituto de Ciencia Molecular (ICMol), Universidad de Valencia , Catedrático José Beltrán 2, 46980 Paterna, Spain.
authors: Eugenio
authors: E
authors: Coronado