Vanadyl-tartaric acid system at low pH. Equilibrium quotients and complexation kinetics

Kustin, Kenneth; Pizer, Richard

doi:10.1021/ic50088a047

Cited by 12 publications

(2 citation statements)

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“…The width of the (-7/2), line in the frozen-solution EPR spectrum arising from these cells is, therefore, not a direct measure of pH (Frank et al, 1986). We note, however, that vanadyl carboxylate complexes are stable to very low pH values (Kustin & Pizer, 1970;Reeder & Rieger, 1971) and appear to have been detected by EPR in vanadocytes from Ascidia méntula (Bell et al, 1982). in ascidian vanadocytes (Tullius et al, 1980;Dingley et al, 1982;Bell et al, 1982;Frank et al, 1986).…”

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A large reservoir of sulfate and sulfonate resides within plasma cells from ascidia ceratodes, revealed by x-ray absorption near-edge structure spectroscopy

et al. 1987

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The study of sulfur within the plasma cells of Ascidia ceratodes [Carlson, R. M. K. (1975) Proc. Natl. Acad. Sci. U.S.A. 72, 2217-2221; Frank, P., Carlson, R. M. K., & Hodgson, K. O. (1986) Inorg. Chem. 25, 470-478; Hedman, B., Frank, P., Penner-Hahn, J. E., Roe, A. L., Hodgson, K. O., Carlson, R. M. K., Brown, G., Cerino, J., Hettel, R., Troxel, T., Winick, H., & Yang, J. (1986) Nucl. Instrum. Methods Phys. Res., Sect. A 246, 797-800] has been extended with X-ray absorption near-edge structure (XANES) spectroscopy. An intense absorption feature at 2482.4 eV and a second feature at 2473.7 eV indicate a large endogenous sulfate concentration, as well as smaller though significant amounts of thiol or thioether sulfur, respectively. A strong shoulder was observed at 2481.7 eV on the low-energy side of the sulfate absorption edge, deriving from a novel type of sulfur having a slightly lower oxidation state than sulfate sulfur. The line width of the primary transition on the sulfur edge of a vanadium (III) sulfate solution was found to be broadened relative to that of sodium sulfate, possibly deriving from the formation of the VSO4+ complex ion [Britton, H. T. S., & Welford, G. (1940) J. Chem. Soc., 761-764; Duffy, J. A., & Macdonald, W. J. D. (1970) J. Chem. Soc., 977-980; Kimura, T., Morinaga, M., & Nakano, J. (1972) Nippon Kagaku Zaishi, 664-667]. Similar broadening appears to characterize the oxidized sulfur types in vanadocytes. A very good linear correlation between oxidation state and peak position (in electronvolts) was found for a series of related sulfur compounds. This correlation was used to determine a 5+ oxidation state for the additional sulfur type at 2481.7 eV. (ABSTRACT TRUNCATED AT 250 WORDS)

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confidence: 77%

A large reservoir of sulfate and sulfonate resides within plasma cells from ascidia ceratodes, revealed by x-ray absorption near-edge structure spectroscopy

et al. 1987

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“…The kinetics and mechanism of the oxidation of [ConL]2~by Br2 and Br3" are reported elsewhere. 1 The present paper describes the study of reaction 1 as a function of pH, in order to determine the kinetics and mechanism of the oxidation of [ConL]2by HOBr and OBr".…”

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Kinetics and mechanism of the oxidation of cobalt(II) aminopolycarboxylate complexes by hypobromous acid and hypobromite ion

Woodruff¹,

Margerum²,

Milano³

et al. 1973

Inorg. Chem.

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Margerum, et al.If the first term in eq A4 is much greater than the others, it is clear that the expression for a4 reduces to 1 as in eq 2 in the text.For cobalt, the single relaxation time is calculated analogously from the linear differential rate equation in one variable.The previously undefined a term isThe oxidation of [ CoIILIz-(L is ethylenediaminetetraacetate, EDTA4-, and trans-l,2-diaminocyclohexane-N,N,N',N'-tetraacetate, CyDTA4-) by bromine is studied as a function of pH. As the pH is increased, the identity of the kinetically important oxidant changes from a mixture of Br, and Br,-to HOBr and finally to OBI-. The reactions are first order in [CoIILI2-concentration and first order in the bromine species. The values of the rate constants (M-' sec-I) for the oxidations by Br,, HOBr, and OBI-when L is EDTA are 7.3 X lo-', 65, and 2000, respectively, and when L is CyDTA, the values are 2.0 X 0.16, and 49, respectively. The product of the oxidation of [CoIIL]'-by HOBr and OBI-is either [CoIII(L)OH2]-or [COIII(L)OH]~-, depending upon pH. Postoxidation ring closure gives [CorlIL]'-where L is six-coor-dinate. This is a fast process for CyDTA and a rapid scan spectrophotometer is used to observe the oxidation and ring closure steps. IntroductionThe cobalt(I1) complexes of EDTA and CyDTA, [Co1'LI2-, are oxidized by bromine species in aqueous solution as shown in eq 1. The reactions are first order in [CoI1LIZ-concentra-

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Kinetische Untersuchungen an Komplexen des Vanadyls mit mehrzähnigen Liganden

Hoffmann

Ulbricht

1972

Ber Bunsenges Phys Chem

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Mit Hilfe einer Drucksprungapparatur wurde die Kinetik der Komplexbildung des Vanadyl‐Kations mit den Chelat‐bildenden Liganden Malonat, Oxalat, L‐Tartrat und racemischem Tartrat untersucht. Dabei wurden an den Systemen VO‐Malonsäure und VO‐Weinsäure jeweils drei Relaxationszeiten gefunden, die beim Malonat der Bildung der Komplexe (VOOH)2‐Mal, VOMal und VOMal2‐2, beim Oxalat der Bildung der Komplexe VOOx sowie der beiden strukturisomeren Komplexe VOOx2äq2−, und VOOx2ax2− zugeordnet wurden. Die gefundenen Geschwindigkeitskonstanten wurden diskutiert. Am System VO‐Weinsäure wurden zwei Relaxationszeiten gefunden, die analog dem Nickeltartrat [14] der Bildung der Komplexe VO ‐ T bzw. VOTH+ und (VO ‐ T)2 zugeordnet wurden. Auch hier wurde gefunden, daβ die Bildung des Doppelkomplexes stereospezifisch in der Weise erfolgt [15], daβ aus je einem VO ‐L‐T und einem VO ‐D‐T kein gemischter Doppelkomplex gebildet wird. Diese Analogie macht eine allgemeine Gültigkeit des Mechanismus der Komplexbildung mit Tartraten wahrscheinlich.

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Vanadyl-tartaric acid system at low pH. Equilibrium quotients and complexation kinetics

Cited by 12 publications

References 3 publications

A large reservoir of sulfate and sulfonate resides within plasma cells from ascidia ceratodes, revealed by x-ray absorption near-edge structure spectroscopy

A large reservoir of sulfate and sulfonate resides within plasma cells from ascidia ceratodes, revealed by x-ray absorption near-edge structure spectroscopy

Kinetics and mechanism of the oxidation of cobalt(II) aminopolycarboxylate complexes by hypobromous acid and hypobromite ion

Kinetische Untersuchungen an Komplexen des Vanadyls mit mehrzähnigen Liganden

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