BIBLIOS

Document type
Journal articles

Document subtype
Full paper

Title
Oxovanadium(IV) complexes of the dipeptides glycyl-L-aspartic acid, L-aspartylglycine and related ligands; a spectroscopic and potentiometric study

Participants in the publication
João Costa Pessoa (Author)
Tamás Gajda (Author)
Robert D. Gillard (Author)
Tamás Kiss (Author)
Susana M. Luz (Author)
José J. G. Moura (Author)
Isabel Tomaz (Author)
Dep. Química e Bioquímica
CQE
João P. Telo (Author)
Ibolya Török (Author)

Summary
The equilibria in the systems VO2+ + L (L = Gly-L-Asp, L-Asp-Gly, N-acetyl-L-aspartic acid or succinic acid) have been studied at 25 degrees C and 0.2 mol dm(3) K(CI) medium by a combination of potentiometric and spectroscopic methods (ESR, circular dichroism and visible absorption). Formation constants were calculated from pH-metric data with total oxovanadium(Iv) concentrations of (0.6-4) x 10(-3) mol dm(-3) and ligand-to-metal (L:M) ratios of 2-8 (AspGly) or 4-15: 1 (other systems). The position of the Asp residue in the peptide chain affects the co-ordination mode of the ligands: while in the GlyAsp system bis complexes start to form at pH less than 2, for AspGly only 1 : 1 complexes form, with relatively high CD signal. The co-ordination behaviour of N-acetyl-L-aspartic and succinic acids is similar. The results of potentiometric and spectroscopic methods are self consistent. Isomeric structures are discussed for each stoichiometry proposed and the results compared with those for L-aspartic acid and dipeptides with non-coordinating side chains.


Where published
Journal of the Chemical Society. Dalton Transactions

Publication Identifiers
ISSN - 0300-9246

Address
Cambridge, United Kingdom

Publisher
Royal Society of Chemistry



Document Identifiers
DOI - http://dx.doi.org/10.1039/a801888j
URL - https://pubs.rsc.org/en/content/articlelanding/1998/DT/a801888j