ISSN:
1588-2780
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Energy, Environment Protection, Nuclear Power Engineering
Notes:
Abstract Ligand exchange reaction of Zn(II)-acetylacetonate complex (Zn-acac2) with 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid (H2TPPS) has been investigated spectrophotometrically and radiometrically. The exchange reaction was observed by spectral change from H2TPPS to Zn-TPPS or activity of65Zn(acac)2 extracted into the chloroform phase. The 2nd order rate constants (k 2) for the exchange reaction at 70 °C and at pH 7.8 were found to be 32.8±2.3 and 31.2±3.2 M−1·s−1 from the spectrometric and radiotracer experiments, respectively. For the direct complexation of Zn(II) with H2TPPS, a similar 2nd order rate constant (k=32.4±4.7 M−1·s−1) was obtained as that in the ligand exchange reaction. The activation energies (E) for the exchange and the formation of Zn-TPPS were found to be 69.3±0.2 and 69.4±0.2 kJ·mol−1, respectively, in the temperature range from 40 to 70 °C.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02042960
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