Kinetics and mechanism of periodate oxidation of two ternary nitrilotriacetatochromium(III) complexes involving histidine and aspartate co-ligands

Hassan A. Ewais; Mohamed A. Habib; Shabaan A.K. Elroby

doi:10.1007/s11243-009-9297-6

Kinetics and mechanism of periodate oxidation of two ternary nitrilotriacetatochromium(III) complexes involving histidine and aspartate co-ligands

Hassan A. Ewais
, Mohamed A. Habib
, Shabaan A.K. Elroby

Research output: Contribution to journal › Article › peer-review

20 Scopus citations

Abstract

The oxidation of [Cr^III(HNTA)(Hist)(H₂O)]^- and [Cr^III(HNTA)(Asp)(H₂O)]^- (NTA = nitrilotriacetate, Hist = l-histidinate and Asp = dl-aspartate) by periodate in aqueous medium has been studied spectrophotometrically between 15.0 and 35.0 °C under pseudo-first-order conditions, [IO₄ ^-] ≫ [complex]. The rate increases over the pH range 3.40-4.45 in both cases, but the two complexes give different rate laws. It is proposed that electron transfer proceeds through an inner-sphere mechanism via coordination of IO₄ ^- to chromium(III). A common mechanism for the oxidation of some chromium(III) complexes by periodate is proposed, and this is supported by an excellent isokinetic relationship between ΔH*and ΔS*values for these reactions.

Original language	English
Pages (from-to)	73-80
Number of pages	8
Journal	Transition Metal Chemistry
Volume	35
Issue number	1
DOIs	https://doi.org/10.1007/s11243-009-9297-6
State	Published - Feb 2010
Externally published	Yes

ASJC Scopus subject areas

Inorganic Chemistry
Metals and Alloys
Materials Chemistry

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title = "Kinetics and mechanism of periodate oxidation of two ternary nitrilotriacetatochromium(III) complexes involving histidine and aspartate co-ligands",

abstract = "The oxidation of [CrIII(HNTA)(Hist)(H2O)]- and [CrIII(HNTA)(Asp)(H2O)]- (NTA = nitrilotriacetate, Hist = l-histidinate and Asp = dl-aspartate) by periodate in aqueous medium has been studied spectrophotometrically between 15.0 and 35.0 °C under pseudo-first-order conditions, [IO4 -] ≫ [complex]. The rate increases over the pH range 3.40-4.45 in both cases, but the two complexes give different rate laws. It is proposed that electron transfer proceeds through an inner-sphere mechanism via coordination of IO4 - to chromium(III). A common mechanism for the oxidation of some chromium(III) complexes by periodate is proposed, and this is supported by an excellent isokinetic relationship between ΔH*and ΔS*values for these reactions.",

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T1 - Kinetics and mechanism of periodate oxidation of two ternary nitrilotriacetatochromium(III) complexes involving histidine and aspartate co-ligands

AU - Ewais, Hassan A.

AU - Habib, Mohamed A.

AU - Elroby, Shabaan A.K.

PY - 2010/2

Y1 - 2010/2

N2 - The oxidation of [CrIII(HNTA)(Hist)(H2O)]- and [CrIII(HNTA)(Asp)(H2O)]- (NTA = nitrilotriacetate, Hist = l-histidinate and Asp = dl-aspartate) by periodate in aqueous medium has been studied spectrophotometrically between 15.0 and 35.0 °C under pseudo-first-order conditions, [IO4 -] ≫ [complex]. The rate increases over the pH range 3.40-4.45 in both cases, but the two complexes give different rate laws. It is proposed that electron transfer proceeds through an inner-sphere mechanism via coordination of IO4 - to chromium(III). A common mechanism for the oxidation of some chromium(III) complexes by periodate is proposed, and this is supported by an excellent isokinetic relationship between ΔH*and ΔS*values for these reactions.

AB - The oxidation of [CrIII(HNTA)(Hist)(H2O)]- and [CrIII(HNTA)(Asp)(H2O)]- (NTA = nitrilotriacetate, Hist = l-histidinate and Asp = dl-aspartate) by periodate in aqueous medium has been studied spectrophotometrically between 15.0 and 35.0 °C under pseudo-first-order conditions, [IO4 -] ≫ [complex]. The rate increases over the pH range 3.40-4.45 in both cases, but the two complexes give different rate laws. It is proposed that electron transfer proceeds through an inner-sphere mechanism via coordination of IO4 - to chromium(III). A common mechanism for the oxidation of some chromium(III) complexes by periodate is proposed, and this is supported by an excellent isokinetic relationship between ΔH*and ΔS*values for these reactions.

UR - https://www.scopus.com/pages/publications/75749110903

U2 - 10.1007/s11243-009-9297-6

DO - 10.1007/s11243-009-9297-6

M3 - Article

AN - SCOPUS:75749110903

SN - 0340-4285

VL - 35

SP - 73

EP - 80

JO - Transition Metal Chemistry

JF - Transition Metal Chemistry

IS - 1

ER -

Kinetics and mechanism of periodate oxidation of two ternary nitrilotriacetatochromium(III) complexes involving histidine and aspartate co-ligands

Abstract

ASJC Scopus subject areas

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