Kinetics and mechanism of oxidation of a ternary complex involving dipicolinatochromium(III) and <scp>DL</scp>‐aspartic acid by <i>N</i>‐bromosuccinimide

Ewais, Hassan A.; Ahmed, Ahmed E.; Abdelkhalek, Ahmed

doi:10.1002/kin.20014

Cited by 4 publications

(5 citation statements)

References 16 publications

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“…The overall stoichiometry of the reaction is determined as 1 mol of Cr(III):2 mol of NBS. It is well established that NBS is a one electron oxidant 16 . The oxidation of aqueous chromium(III) ion as well as that of several of its complexes in acidic media that lead to chromium(VI), the stoichiometry has been, without exception, 1 mol of Cr(III):3 mol NBS 17 .…”

Section: Resultsmentioning

confidence: 99%

Biphasic oxidation of diaquadichloro(1,10‐phenanthroline)chromium(III) by N‐bromosuccinimide and the formation of chromium(IV) and chromium(V)

Elsiddig

Sulfab

2022

Int J of Chemical Kinetics

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The kinetics of oxidation of diaquadichloro(1,10-phenanthroline)chromium(III) complex, [Cr III (phen)(H 2 O) 2 Cl 2 ] + , by N-bromosuccinimide (NBS) is biphasic.The first faster step involves the oxidation of Cr(III) to Cr(IV). The second slower step is due to the oxidation of Cr(IV) to Cr(V). The reaction product is isolated and characterized by electron spin resonance (ESR), IR, and elemental analysis. The chromium(V) product is consistent with the formula [Cr V (phen)Cl 2 (O)]Br. The rate constants k f and k s , for the faster and the slower steps respectively, were obtained using an Origin 9.0 software program. Values of both k f and k s , varied linearly with [NBS] at constant reaction conditions. The effect of pH on the reaction rate is investigated over the pH (4.11-6.01) range at 25.0 • C. The rate constants k f and k s increased with increasing pH. This is consistent with hydroxo forms of the chromium species being more reactive than the aqua forms. Chromium(III) complexes, more often than not, are inert. The oxidation of the Cr(III) complex to Cr(IV), most likely, proceeds by an outer sphere mechanism. Since chromium(IV) is labile the mechanism of its oxidation to chromium(V) is not certain.

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Section: Resultsmentioning

confidence: 99%

Biphasic oxidation of diaquadichloro(1,10‐phenanthroline)chromium(III) by N‐bromosuccinimide and the formation of chromium(IV) and chromium(V)

Elsiddig

Sulfab

2022

Int J of Chemical Kinetics

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“…N-bromosuccinimide is a cheap and convenient oxidant which has been used for oxidation of some inorganic transition metal complexes (1)(2)(3)(4)(5)(6)(7)(8) . The kinetics and mechanism of oxidation of a ternary complex involving dipicolinato-chromium (III) (1) and DL-aspartic acid by N-bromosuccin-imide have been studied.…”

Section: Abstract: Kinetics Oxidation Of Cobalt (Ii) Complex and Oximentioning

confidence: 99%

“…The kinetics and mechanism of oxidation of a ternary complex involving dipicolinato-chromium (III) (1) and DL-aspartic acid by N-bromosuccin-imide have been studied. The experimental rate law was consistent with a mechanism in which the deprotonated [Cr…”

Section: Abstract: Kinetics Oxidation Of Cobalt (Ii) Complex and Oximentioning

confidence: 99%

Inner-sphere Oxidation of Acetato- diaqua-(2-hydroxobenzy- lidene)- 5- phenylthiazol- 2- amino Cobalt (II) Complex by N-bromosuccinimide

2012

Egypt. J. Chem.

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The experimental rate law was consistent with a mechanism in which the deprotonated form of the complex was considered as more reactive than its conjugate acid. Polymerization of acrylonitrile was taken as an evidence for the presence of free radical in the reaction mixture. It was assumed that electron transfer took place via an inner-sphere mechanism through the formation of the initial cobalt (III) products which were slowly converted to the final cobalt (III) products.

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“…Oxidations of some binary [4][5][6][7][8][9][10][11][12][13][14] and ternary [5,[15][16][17] Cr III complexes were studied, proceeding via an inner-sphere mechanism.…”

Section: Introductionmentioning

confidence: 99%

Two-step one-electron transfer reaction of chromium(III) complex containing levodopa and uridine with N-bromosuccinimide

Abdelkhalek

Adawi²,

Abdel-Hafeez³

2012

Journal of Coordination Chemistry

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Cr III (LD)(Urd)(H 2 O) 4 ](NO 3 ) 2 Á 3H 2 O (LD ¼ Levodopa; Urd ¼ uridine) was prepared and characterized. The product of the oxidation reaction was examined using HPLC. Kinetics of the oxidation of [Cr III (LD)(Urd)(H 2 O) 4 ] 2þ with N-bromosuccinimide (NBS) in an aqueous solution was studied spectrophotometrically, with 1.0-5.0 Â 10 À4 mol dm À3 complex, 0.5-5.0 Â 10 À2 mol dm À3 NBS, 0.2-0.3 mol dm À3 ionic strength (I), and 30-50 C. The reaction is first order with respect to [Cr III ] and [NBS], decreases as pH increases in the range 5.46-6.54 and increases with the addition of sodium dodecyl sulfate (SDS, 0.0-1.0 Â 10 À3 mol dm À3 ). Activation parameters including enthalpy, DH*, and entropy, DS*, were calculated. The experimental rate law is consistent with a mechanism in which the protonated species is more reactive than its conjugate base. It is assumed that the two-step one-electron transfer takes place via an inner-sphere mechanism. A mechanism for this reaction is proposed and supported by an excellent isokinetic relationship between DH* and DS* for some Cr III complexes. Formation of [Cr III (LD)(Urd)(H 2 O) 4 ] 2þ in vivo probably occurs with patients who administer the anti-Parkinson drug (Levodopa), since Cr III is a natural food element. This work provides an opportunity to identify the nature of such interactions in vivo similar to that in vitro.

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Kinetics and mechanism of oxidation of a ternary complex involving dipicolinatochromium(III) and DL‐aspartic acid by N‐bromosuccinimide

Abstract: The kinetics of oxidation of [Cr III (Dpc)(Asp)(H 2 O) 2 ] (Dpc = dipicolinic acid and Asp = DL-aspartic acid) by N-bromosuccinimide (NBS) in aqueous solution have been found to obey the equation:where k 2 is the rate constant for the electron transfer process,

Cited by 4 publications

References 16 publications

Biphasic oxidation of diaquadichloro(1,10‐phenanthroline)chromium(III) by N‐bromosuccinimide and the formation of chromium(IV) and chromium(V)

Biphasic oxidation of diaquadichloro(1,10‐phenanthroline)chromium(III) by N‐bromosuccinimide and the formation of chromium(IV) and chromium(V)

Inner-sphere Oxidation of Acetato- diaqua-(2-hydroxobenzy- lidene)- 5- phenylthiazol- 2- amino Cobalt (II) Complex by N-bromosuccinimide

Two-step one-electron transfer reaction of chromium(III) complex containing levodopa and uridine with N-bromosuccinimide

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