Structures and Magnetic Properties of Iron(III) Dinuclear Complexes with Alkoxo and Carboxylato Bridges

Masako Kato, Yasuko Yamada, Tomoko Inagaki, Wasuke Mori, Ken Sakai, Taro Tsubomura, Mitsunobu Sato, Shigenobu Yano

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27 Citations (Scopus)

Abstract

A series of diiron(III) complexes containing alkoxo and carboxylato bridges, [Fe2(dhpta)(OOCR)(H2O)2] (H5-dhpta = l,3-diamino-2-hydroxypropane-N,N,N’,N’-tetraacetic acid; R = C6H4OH (1), CH2CH=CH2 (2), C6H4-NH2 (3), CH2CH2Br (4); CH=CHCH3 (5)) have been synthesized. Their molecular structures and magnetic properties were investigated. For land 2, the crystal structures have been determined by X-ray analysis. Crystal data: for 1, dihydrate, triclinic, P1, a = 9.929(3) Å, b = 18.955(6) Å, c = 7.862(2) Å, α = 113.60(2)°, β = 107.57(2)°, γ = 61.79(3)°, V = 1182.2(7) Å3, Z = 2, R = 0.050; for 2, triclinic, P1, a = 10.020(1) Å, b = 15.952(1) Å, c = 6.7523(7) Å, α = 95.536(7)°, β = 97.968(8)°, γ = 86.612(7)°, V = 1062.7(2) Å3, Z = 2, R = 0.050. For both complexes, two Fe(III) ions take rather distorted octahedral structure and are bridged by the alkoxyl group of dhpta and the carboxylate ion. Fe-O(R) distances are 2.006(2) and 1.985(2) Å for 1 and 1.971(4) and 1.998(3) Å for 2, and the Fe-O(R)-Fe angle is 130.0(1)° for 1 and 130.2(2)° for 2. EXAFS, XANES, and IR data support that all the complexes have similar (μ-alkoxo)(μ-carboxylato)diiron dimer structures. Independent of the bridging carboxylate ligand, all these complexes exhibit similar weak antiferromagnetic exchange interactions between the spins of the ferric ions through the O(-R) bridge (-J = 14–16 cm−1). Among these complexes, a small but significant increase in the -J value with shorter Fe-(μ-O) distance is noted. This indicates that the spin exchange interaction is very sensitive to the bond length between Fe and bridging oxygen atoms also for the (μ-alkoxo)diiron(III) complexes. Both 1 and 2 have the crystal structures with a separate arrangement of hydrophilic and hydrophobic parts and stacking of the π system.

Original languageEnglish
Pages (from-to)2645-2651
Number of pages7
JournalInorganic chemistry
Volume34
Issue number10
DOIs
Publication statusPublished - May 1 1995
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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