ISSN:
1040-0397
Schlagwort(e):
DPP
;
Speciation
;
Labile metal complexes
;
Complex formation curves
;
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The PbII-N,N′-di-2-picolylethylenediamine (DPA-2) system was studied by differential pulse polarography (DPP) and glass electrode potentiometry (GEP) at fixed total-ligand to total-metal concentration ratio and varied pH. The polarographic experimental complex formation curve (ECFC) and calculated complex formation curve (CCFC) are used for modeling of a metal-ligand system and the refinement of stability constants. The ECFC is used instead of a shift in the peak potential plotted vs. pH and it appears to be a characteristic function for a particular metalligand system. The CCFC is a theoretical curve calculated for the assumed metal-ligand model from mass-balance equations. The final model of metal species formed is the one which is accepted by these two experimental techniques and for which stability constants of metal complexes obtained from DPP and GEP differ the least. Four lead complexes Pb(HL), PbL, PbL2(OH) and PbL(OH)2 and their stability constants as log β found from DPP 12.67 ± 0.08, 9.68 ± 0.07, 16.12 ± 0.08 and 14.88 ± 0.06, respectively, are reported. Results obtained from GEP and DPP differ only within experimental errors typical for these techniques.
Zusätzliches Material:
5 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/elan.1140090909
