A kinetic study of pyrophosphate and peroxodiphosphate complexation of oxovanadium(IV) ion
Abstract
The formation constant of the vanadyl pyrophosphate complex, VO(H_2P_2O_7), determined spectrophotometrically in acidic 1.0 M NaClO_4 solution, is logK = 4.4±0.1 at 25°C. The kinetics of the complexation of vanadyl ion by pyrophosphate and peroxodiphosphate were studied at pH 2.0 using stopped-flow spectrophotometry. The reactions are first-order in ligand and in vanadyl ion with rate constants k_2 = 2.3×10^4 and 7.5×10^3 M^(−1) sec^(−1) at 12°C for H_2P_2O_7^(2−) and H_2P_2O_8^(2−), respectively. The complexation reactions were followed by slower secondary processes which are attributed to polymerization. The results for the complexation reactions are consistent with an interchange mechanism for the formation of a monodentate complex, followed by rapid closure of the chelate ring. Peroxodisulfate, studied under similar conditions, showed no evidence of innersphere complexation.
Additional Information
© 1976 Elsevier. Received February 24, 1976. Taken in part from the Ph.D. Thesis of M. R. H., Brown University, 1973. Stimulating discussions with M. W. Kendig and N. D. Chasteen are gratefully acknowledged. This work was supported in part by FMC Corporation and the Air Force Office of Scientific Research.Additional details
- Eprint ID
- 62942
- DOI
- 10.1016/S0020-1693(00)91092-2
- Resolver ID
- CaltechAUTHORS:20151215-112214021
- FMC Corporation
- Air Force Office of Scientific Research (AFOSR)
- Created
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2015-12-15Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field