Novel square arrangements in tetranuclear and octanuclear iron(III) complexes with asymmetric iron environments created by the unsymmetric bridging ligand N,N,N{prime}-tris((N-methyl)-2-benzimidazolylmethyl)-N{prime}-methyl-1,3-diamino-2-propanol
- Lawrence Livermore National Lab., CA (United States)
- Univ. of California, Davis, CA (United States). Dept. of Chemistry
- Catholic Univ. of America, Washington, DC (United States)
The synthesis and characterization of novel tetranuclear and octanuclear iron(III) complexes with structures based on a nearly square arrangement of four iron ions are reported. Reaction of ferric nitrate, sodium acetate, and the unsymmetrical binucleating ligand HBMDP, where HBMDP is N,N,N{prime}-tris((N-methyl)-2-benzimidazolylmethyl)-N{prime}-methyl-1,3-diamino-2-propanol, in acetone/water yields the tetranuclear iron complex [Fe{sub 4}({mu}-O){sub 2}({mu}-BMDP){sub 2}-({mu}-OAc){sub 2}]{sup 4+}, which exhibits coordination number asymmetry. The structure of [Fe{sub 4}({mu}-O){sub 2}({mu}-BMDP){sub 2}({mu}-OAc){sub 2}](NO{sub 3}){sub 3}(OH){center_dot}12H{sub 2}O has been determined by single-crystal X-ray diffraction. Each ({mu}-BMDP) ligand spans two iron(III) ions and causes these ions to become structurally distinct. Within this binuclear unit one iron atom is five-coordinate with distorted square pyramidal geometry and an N{sub 2}O{sub 3} donor set, while the other iron is six-coordinate with distorted octahedral geometry and an N{sub 3}O{sub 3} donor set. Two of these binuclear units are linked through a pair of oxo and acetato bridges to form the centrosymmetric tetranuclear complex. Efforts to increase the solubility of [Fe{sub 4}({mu}-O){sub 2}({mu}-BMDP){sub 2}({mu}-OAc){sub 2}]{sup 4+} by metathesis with sodium tetrafluoroborate resulted in the isolation of crystals of a new octanuclear iron species, which has also been characterized by single-crystal X-ray diffraction.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 316225
- Journal Information:
- Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 26 Vol. 37; ISSN 0020-1669; ISSN INOCAJ
- Country of Publication:
- United States
- Language:
- English
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