oa South African Journal of Chemistry - Speciation of Co(II), Ni(II) and Cu(II) complexes with L-glutamic acid in dioxan-water mixtures

Volume 64, Issue 1
  • ISSN : 0379-4350



Chemical speciation of Co(II), Ni(II) and Cu(II) complexes of L-glutamic acid in the presence of Dioxan-Water mixtures at an ionic strength of 0.16 mol L-1 at 303K was studied pH-metrically. Glu is taken as a model compound for amino acid residues and dioxan is used to mimic the low dielectric constant at the active site cavities in bioactive molecules like enzymes and proteins. The active forms of the ligand were LH+, LH, LH- and L2-. The models containing different numbers of species were refined using the computer program, MINIQUAD75. The predominant species detected were MLH, MLH-, ML2-, MLH+ and ML. The best fit chemical models were arrived at based on statistical parameters. The trend in variation of complex stability constants with the medium composition was explained on the basis of changes in the dielectric constant of the solution. Effect of errors in the ingredients on the stability constants was also studied. Chemical speciation is discussed based on the distribution diagrams.

Loading full text...

Full text loading...


Article metrics loading...


This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error