Synthesis and characterization of the tetranuclear iron(III) complex of a new asymmetric multidentate ligand. A structural model for purple acid phosphatases

Dalton Trans. 2007 Nov 28:(44):5132-9. doi: 10.1039/b709293h. Epub 2007 Sep 6.

Abstract

The ligand, 2-((2-hydroxy-5-methyl-3-((pyridin-2-ylmethylamino)methyl)benzyl)(2-hydroxybenzyl)amino)acetic acid (H(3)HPBA), which contains a donor atom set that mimics that of the active site of purple acid phosphatase is described. Reaction of H(3)HPBA with iron(III) or iron(II) salts results in formation of the tetranuclear complex, [Fe(4)(HPBA)(2)(OAc)(2)(mu-O)(mu-OH)(OH(2))(2)]ClO(4) x 5H(2)O. X-Ray structural analysis reveals the cation consists of four iron(III) ions, two HPBA(3-) ligands, two bridging acetate ligands, a bridging oxide ion and a bridging hydroxide ion. Each binucleating HPBA(3-) ligand coordinates two structurally distinct hexacoordinate iron(III) ions. The two metal ions coordinated to a HPBA(3-) ligand are linked to the two iron(III) metal ions of a second, similar binuclear unit by intramolecular oxide and hydroxide bridging moieties to form a tetramer. The complex has been further characterised by elemental analysis, mass spectrometry, UV-vis and MCD spectroscopy, X-ray crystallography, magnetic susceptibility measurements and variable-temperature Mössbauer spectroscopy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / chemistry*
  • Acid Phosphatase / chemistry*
  • Crystallography, X-Ray
  • Ferric Compounds* / chemical synthesis
  • Ferric Compounds* / chemistry
  • Ferrous Compounds* / chemical synthesis
  • Ferrous Compounds* / chemistry
  • Glycoproteins / chemistry*
  • Hydrogen Bonding
  • Ligands
  • Magnetic Resonance Spectroscopy / methods
  • Magnetics
  • Mass Spectrometry / methods
  • Models, Molecular
  • Molecular Structure
  • Pyridines / chemistry*
  • Spectrophotometry, Ultraviolet / methods
  • Spectroscopy, Mossbauer / methods

Substances

  • 2-((2-hydroxy-5-methyl-3-((pyridin-2-ylmethylamino)methyl)benzyl)(2-hydroxybenzyl)amino)acetic acid
  • Acetates
  • Ferric Compounds
  • Ferrous Compounds
  • Glycoproteins
  • Ligands
  • Pyridines
  • purple acid phosphatase
  • Acid Phosphatase