Glyphosate complexation to aluminium(III). An equilibrium and structural study in solution using potentiometry, multinuclear NMR, ATR-FTIR, ESI-MS and DFT calculations

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The stoichiometries and stability constants of a series of Al(3+)-N-phosponomethyl glycine (PMG/H(3)L) complexes have been determined in acidic aqueous solution using a combination of precise potentiometric titration data, quantitative (27)Al and (31)P NMR spectra, ATR-FTIR spectrum and ESI-MS measurements (0.6 M NaCl, 25 degrees C). Besides the mononuclear AlH(2)L(2+), Al(H(2)L)(HL), Al(HL)(2)(-) and Al(HL)L(2-), dimeric Al(2)(HL)L(+) and trinuclear Al(3)H(5)L(4)(2+) complexes have been postulated. (1)H and (31)P NMR data show that different isomers co-exist in solution and the isomerization reactions are slow on the (31)P NMR time scale. The geometries of monomeric and dimeric complexes likely double hydroxo bridged and double phosphonate bridged isomers have been optimized using DFT ab initio calculations starting from rational structural proposals. Energy calculations using the PCM solvation method also support the co-existence of isomers in solutions. (C) 2009 Elsevier Inc. All rights reserved.


  • Mihaly Purgel
  • Zoltan Takacs
  • Caroline M. Jonsson
  • Lajos Nagy
  • Ingegard Andersson
  • Istvan Banyai
  • Imre Papai
  • Per Persson
  • Staffan Sjoberg
  • Imre Toth
External organisations
  • External Organization - Unknown
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biochemistry and Molecular Biology
Original languageEnglish
Pages (from-to)1426-1438
JournalJournal of Inorganic Biochemistry
Publication statusPublished - 2009
Publication categoryResearch
Externally publishedYes

Bibliographic note