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dc.contributor.authorChang, C. Allenen_US
dc.contributor.authorChen, Yu-Pingen_US
dc.contributor.authorHsiao, Chih-Hsiangen_US
dc.date.accessioned2014-12-08T15:09:56Z-
dc.date.available2014-12-08T15:09:56Z-
dc.date.issued2009-03-01en_US
dc.identifier.issn1434-1948en_US
dc.identifier.urihttp://dx.doi.org/10.1002/ejic.200801038en_US
dc.identifier.urihttp://hdl.handle.net/11536/7587-
dc.description.abstractKinetic studies of hydrolysis reactions of BNPP [sodium bis(p-nitrophenyl) phosphate] with trivalent lanthanide (Ln(3+)) complexes of HEDTA [HEDTA = N-hydroxyethyl(ethylenediamine)-N,N',N'-triacetate] were performed at pH 6.96-11.34 and 25 degrees C by a spectrophotometric method and by HPLC analysis. The reaction rates increase with increasing atomic number of lanthanide and solution pH from PrHEDTA to EuHEDTA and then decrease for heavier LnHEDTA complexes. Plots of pseudo-first-order rate constants (k(obs)) vs. pH could be fitted to the equation k(obs) = k(LnL(OH))[LnL](T)/{1+exp-[-2.303(pH-pK(h))]} where K(LnL(OH)) is the rate constant for the reaction of LnHEDTA(OH)(-) with BNPP, K(h) is the hydrolysis constant of LnHEDTA, and [LnL](T) is the total concentration of LnHEDTA. The pK(h) values obtained by the kinetic method are in the range 8.2-10.3 and are similar to those measured by potentiometric methods. At [LnL](T) = 10-70 mM and pH 10.5, most of the observed pseudo-first-order rate constants could be fitted to a simple saturation kinetic model, k(obs) = K(1)K[LnHEDTA(OH)(-)]/[1 + K[LnHEDTA(OH)(-)]}, where K is the equilibrium constant for the formation for LnHEDTA(OH)(-)BNPP and is in the range 2-147 M(-1). The k(1) values are in the range 1.12X10(-5)-2.71 X 10(-3) s(-1). The k(obs) data for TbHEDTA and HoHEDTA were fitted to a quadratic equation. It was observed that the dinuclear species are more reactive. ESI mass spectrometry confirmed that the reaction between BNPP and EuHEDTA is a simple hydrolysis but not a transesterification, presumably because the three inner-sphere coordinated water molecules are far away from the coordinated hydroxyethyl group. Hydrolysis is likely to occur by proton transfer from one inner-sphere coordinated water molecule to the deprotonated ethyl oxide group followed by nucleophilic attack of the resulting hydroxide ion on the bonded BNPP anion, ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)en_US
dc.language.isoen_USen_US
dc.subjectLanthanidesen_US
dc.subjectHydrolysisen_US
dc.subjectKineticsen_US
dc.subjectMacrocyclic complexesen_US
dc.subjectPhosphodiestersen_US
dc.subjectReaction mechanismsen_US
dc.titleKinetics of Bis(p-nitrophenyl)phosphate (BNPP) Hydrolysis Reactions with Trivalent Lanthanide Complexes of N-Hydroxyethyl(ethylenediamine)-N,N ', N '-triacetate (HEDTA)en_US
dc.typeArticleen_US
dc.identifier.doi10.1002/ejic.200801038en_US
dc.identifier.journalEUROPEAN JOURNAL OF INORGANIC CHEMISTRYen_US
dc.citation.volumeen_US
dc.citation.issue8en_US
dc.citation.spage1036en_US
dc.citation.epage1042en_US
dc.contributor.department生物科技學系zh_TW
dc.contributor.departmentDepartment of Biological Science and Technologyen_US
dc.identifier.wosnumberWOS:000264683200007-
dc.citation.woscount3-
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