Please use this identifier to cite or link to this item: http://nopr.niscair.res.in/handle/123456789/14533
Title: Two step one-electron transfer reaction of chromium(III) complex containing carbidopa and inosine with N-bromosuccinimide
Authors: Abdel-Khalek, Ahmed A
Abdel-Hafeez, Mahmoud M
Keywords: Kinetics
Reaction mechanisms
Carbidopa
Inosine
Chromium
Electron transfer
Issue Date: Aug-2012
Publisher: NISCAIR-CSIR, India
Abstract: <span style="font-size:11.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">Oxidation of [Cr<sup>III</sup>(CD)(Ino)(H<sub>2</sub>O)<sub>4</sub>]<sup>2+ </sup>(where CD = carbidopa, Ino = inosine) with N-bromosuccinimide (NBS) was studied kinetically in aqueous media over varying ranges of concentrations of complex (1.0-5.0) × 10<sup>-4</sup> mol dm<sup>-3  </sup>and NBS (0.5-5.0) × 10<sup>-2</sup> mol dm<sup>-3</sup>,<sup> </sup><i style="mso-bidi-font-style:normal">p</i>H,<sup> </sup>ionic strength and temperature. The reaction is first order with respect to [Cr<sup>III</sup>] and [NBS]. The rate of reaction increases with increasing <i style="mso-bidi-font-style: normal">p</i>H over the studied range (6.76-7.84). The anionic surfactant, sodium dodecyl sulphate is found to increase the rate of the oxidation in the range (0.0-1.0) × 10<sup>-3 </sup>mol dm<sup>-3</sup>. Thermodynamic activation parameters have also been calculated. The rate of oxidation obeys the equation <i style="mso-bidi-font-style:normal">d</i>[Cr<sup>VI</sup>]/<i style="mso-bidi-font-style:normal">dt</i> = {<i>k</i><sub><span style="font-size:11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:"courier="" new";mso-ansi-language:en-gb;="" mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">3 </span></sub><span style="font-size:11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:"courier="" new";mso-ansi-language:en-gb;="" mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">+ <i><span style="font-size:11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:mangal;mso-ansi-language:en-gb;="" mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">k</span></i><sub><span style="font-size:11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:"courier="" new";mso-ansi-language:en-gb;="" mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">2 </span></sub><span style="font-size:11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:"courier="" new";mso-ansi-language:en-gb;="" mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">(1/<span style="font-size:11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:mangal;mso-ansi-language:en-gb;="" mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">[H<sup>+</sup>])<span style="font-size:11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:"courier="" new";mso-ansi-language:en-gb;="" mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">}<span style="font-size:11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:mangal;mso-ansi-language:en-gb;="" mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">[NBS][[Cr<sup>III</sup>(CD)(Ino)(H<sub>2</sub>O)<sub>4</sub>]<sup>2+</sup>]<span style="font-size:11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:"courier="" new";mso-ansi-language:en-gb;="" mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">.<span style="font-size:11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:mangal;mso-ansi-language:en-gb;="" mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB"> The experimental rate law is consistent with the proposed mechanism in which the protonated and deprotonated species are involved in the rate determing step. It is proposed that a two step one-electron transfer takes place via an inner sphere mechanism. </span></span></span></span></span></span></span></span>
Description: 1073-1079
URI: http://hdl.handle.net/123456789/14533
ISSN: 0975-0975(Online); 0376-4710(Print)
Appears in Collections:IJC-A Vol.51A(08) [August 2012]

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