TY - JOUR
T1 - Supramolecular spin-crossover iron complexes based on imidazole-imidazolate hydrogen bonds
AU - Sunatsuki, Yukinari
AU - Ohta, Hiromi
AU - Kojima, Masaaki
AU - Ikuta, Yuichi
AU - Goto, Yoshiyuki
AU - Matsumoto, Naohide
AU - Iijima, Seiichiro
AU - Akashi, Haruo
AU - Kaizaki, Sumio
AU - Dahan, Françoise
AU - Tuchagues, Jean Pierre
PY - 2004/7/12
Y1 - 2004/7/12
N2 - 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, [Fe II(H1.5L)](BF4)0.5 (2) (=[Fe II(H3L)][FeII(L)]BF4), [Fe-(H 1.5L)]BF4 (3) (=[FeII(H3L)][Fe III(L)](BF4)2), [FeIII(H 3L)](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 Fe II 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 Fe II-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.
AB - 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, [Fe II(H1.5L)](BF4)0.5 (2) (=[Fe II(H3L)][FeII(L)]BF4), [Fe-(H 1.5L)]BF4 (3) (=[FeII(H3L)][Fe III(L)](BF4)2), [FeIII(H 3L)](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 Fe II 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 Fe II-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.
UR - http://www.scopus.com/inward/record.url?scp=3142658003&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=3142658003&partnerID=8YFLogxK
M3 - Article
C2 - 15236527
AN - SCOPUS:3142658003
SN - 0020-1669
VL - 43
SP - 4154
EP - 4171
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 14
ER -