Details

Autor(en) / Beteiligte

• Sunatsuki, Yukinari
• Ohta, Hiromi
• Kojima, Masaaki
• Ikuta, Yuichi
• Goto, Yoshiyuki
• Matsumoto, Naohide
• Iijima, Seiichiro
• Akashi, Haruo
• Kaizaki, Sumio
• Dahan, Françoise
• Tuchagues, Jean-Pierre

Titel

Supramolecular Spin-Crossover Iron Complexes Based on Imidazole−Imidazolate Hydrogen Bonds

Ist Teil von

• Inorganic chemistry, 2004-07, Vol.43 (14), p.4154-4171

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2004

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The [FeII(H3L)](BF4)2·3H2O (1) complex was synthesized, where H3L (tris{[2-{(imidazole-4-yl)methylidene}amino]ethyl}amine) is a tripodal ligand obtained by condensation of tris(2-aminoethyl)amine and 4-formylimidazole (fim) in a 1:3 molar ratio. Starting from 1, a series of complexes, [FeII(H1.5L)](BF4)0.5 (2) (=[FeII(H3L)][FeII(L)]BF4), [Fe(H1.5L)]BF4 (3) (=[FeII(H3L)][FeIII(L)](BF4)2), [FeIII(H3L)](BF4)3·fim·H2O (4), and [FeIII(L)]·2.5H2O (5), has been synthesized and characterized. The single-crystal X-ray structure of each complex has been determined. The FeII compound, 2, and a mixed valence FeII−FeIII compound, 3, involve formally hemi-deprotonated ligands, H1.5L. The structure of 3 consists of a homochiral two-dimensional assembled sheet, arising from the intermolecular hydrogen bonds between [FeII(H3L)]2+ and [FeIII(L)]0 (3). All but 5 exhibit spin crossover between low-spin (LS) and high-spin (HS) states. This is a rare case where both FeII and FeIII complexes containing the same ligand exhibit spin-crossover behavior. Magnetic susceptibility and Mössbauer studies showed that 3 has three accessible electronic states:  LS FeII−LS FeIII, HS FeII−LS FeIII, and HS FeII−HS FeIII. Compounds 1−3 show the light-induced excited spin-state trapping effect at the FeII sites upon irradiation with green light. The solution magnetic properties, electronic spectra, and electrochemical properties of 1, 4, and 5 were also studied.