Kinetics of the dissociation of binuclear oxygen-bridged complexes of iron(III) with 1,10-phenanthroline and 2,2'-bipyridine

David, P. G.; MELLO, P. C. DE

doi:10.1021/ic50127a052

Cited by 17 publications

(5 citation statements)

References 2 publications

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“…The monodentate ligands (H 2 O or OH ) ) bound to the high-spin d 5 iron(III) are labile [7a] and an inner sphere binding of H 2 Q to the iron center is thus not a remote possibility. It was welldemonstrated that a solution of ½L 4 Cl 2 ðl-OÞFe 2 2þ [22] rapidly aquates to generate ½L 4 ðH 2 OÞ 2 ðl-OÞFe III 2 4þ and also instantaneously produces ½L 4 (SCN) 2 ðl-OÞ Fe III 2 2þ on adding KSCN solution (L = 2,2¢-bipyridine or 1,10-phenanthroline) [22,23]. We further observed that k 0 decreases significantly in presence of added chloride ( Table 1) that may be due to the competitive process where non-reducing Cl ) ions, present in heavy excess competes with H 2 Q for the adduct formation.…”

Section: Mechanismmentioning

confidence: 99%

Mechanistic Studies on the Oxidation of Hydroquinone by an Oxo-bridged Diiron(III,III) Complex in Weakly Acidic Aqueous Media

Bhattacharyya

Mukhopadhyay

2006

Transition Met Chem

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The kinetics of oxidation of hydroquinone (H 2 Q) by a l-oxo-bridged diiron(III,III) complex, ½Fe 2 ðl-OÞ-ðphenÞ 4 ðH 2 OÞ 2 4þ (1) has been investigated in aqueous media at 25.0°C in presence of an excess of 1,10-phenanthroline (phen). The overall redox rate increases with increase in [H + ]. The title complex (1) and its conjugate bases, [Fe 2 ðl-OÞðphenÞ 4 ðH 2 OÞ(OH) 3þ (2) and [Fe 2 ðl-OÞðphenÞ 4 ðOHÞ 2 2þ (3), participate in the reaction with H 2 Q as the only kinetically reactive reducing species. Rate constants (in dm 3 mol )1 s )1 ) for the parallel reactions ð1Þ þ H 2 Q À! Products; ð2Þ þ H 2 Q À! Products and that for ð3Þ þ H 2 Q À! Products are, respectively, 500±40, 100±6 and 30±2. Substantial rate retardation in D 2 O media in comparison to that in H 2 O media suggests that electron transfer is coupled with proton movements in the rate-determining step.

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Section: Mechanismmentioning

confidence: 99%

Mechanistic Studies on the Oxidation of Hydroquinone by an Oxo-bridged Diiron(III,III) Complex in Weakly Acidic Aqueous Media

Bhattacharyya

Mukhopadhyay

2006

Transition Met Chem

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“…On the other hand, Phen and Bipy do not bind Fe(III) ions stably. The decomposition mechanisms of Phen-Fe(III) , and Bipy-Fe(III) , complexes have been proposed to interpret why Phen-Fe(III) and Bipy-Fe(III) complexes are easily decomposed. It is well-known that in aqueous solution the stable ion species are Fe(III) and Cu(II) rather than Fe(II) and Cu(I) ions.…”

Section: Introductionmentioning

confidence: 99%

Silica-Based 2-Aminomethylpyridine Functionalized Adsorbent for Hydrometallurgical Extraction of Low-Grade Copper Ore

et al. 2012

Ind. Eng. Chem. Res.

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A silica-based 2-aminomethylpyridine functionalized adsorbent was synthesized to extract copper. Characterization of the adsorbent was carried out to determine the surface morphology, specific surface area, pore size, and grafting ratio of 2-aminomethylpyridine groups. The adsorption selectivity of the adsorbent for Cu(II) ions was 1353 times higher than that for Fe(III) ions. The adsorption capacity for Cu(II) ions maintained a stable value of 0.53 mmol/g with and without perturbation of Fe(III) ions. Density functional theory (DFT) calculations revealed a mechanism of selective adsorption of copper, through the formation of 2-aminomethylpyridine-Cu(II) complexes. Semi-industrial scale experiments revealed that Cu(II) ions in the acidic leachate of low-grade copper ore could be efficiently extracted by the adsorbent even in perturbation of substantial amounts of Fe(III) and other metal ions. Based on the adsorbent, a new process for copper hydrometallurgical extraction was developed, in which the adverse environmental impacts in traditional solvent extraction processes could be avoided.

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“…The chemistry of oxo-bridged iron(III) dimeric systems is being followed with keen interest as evident from the large volume of literature [1][2][3][4][5][6][7][8][9][10][11][12]. This is due to the probable occurrence of dimeric Fe(III) complexes in biochemical systems such as the protein hemerythrin [10,11,13,14].…”

Section: Introductionmentioning

confidence: 99%

“…Also, dimeric ferriporphyrins containing the Fe-O-Fe structural unit have been identified [15][16][17]. Most of these studies have focused on synthesis [1,2,4,7,12], characterization [5][6][7] and stability in aqueous and acidic media [5,8]. The need for the proper understanding of these systems, as an aid to the understanding of the above biochemical systems, has motivated our interest into probing the election transfer reactions of oxo-bridged iron(III) dimeric ion.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of the reduction of tetrakis (2,2′-bipyridine)-μ-oxo-di-iron(III) by 1,3-benzenediol in aqueous acidic medium

Idris

Iyun

Agbaji

2008

Transition Met Chem

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The stoichiometry and kinetics of the reduction of Fe 2 (III)(bpy) 4 OCl 4 by 1,3-benzenediol have been investigated in aqueous hydrochloric acid medium. The reaction is first order in [oxidant] but zero order in [reductant]. There is no evidence for the formation of an intermediate complex of significant stability. The presence of NO 3 -or ClO 4 -had no effect on the rate of the reaction. Also, the reaction rate is not affected by the changes in the ionic strength and dielectric constant of the reaction media. A plausible mechanism involving an outer-sphere complex formed via an ion pair is proposed for the reaction.

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Kinetics of the dissociation of binuclear oxygen-bridged complexes of iron(III) with 1,10-phenanthroline and 2,2'-bipyridine

Cited by 17 publications

References 2 publications

Mechanistic Studies on the Oxidation of Hydroquinone by an Oxo-bridged Diiron(III,III) Complex in Weakly Acidic Aqueous Media

Mechanistic Studies on the Oxidation of Hydroquinone by an Oxo-bridged Diiron(III,III) Complex in Weakly Acidic Aqueous Media

Silica-Based 2-Aminomethylpyridine Functionalized Adsorbent for Hydrometallurgical Extraction of Low-Grade Copper Ore

Kinetics of the reduction of tetrakis (2,2′-bipyridine)-μ-oxo-di-iron(III) by 1,3-benzenediol in aqueous acidic medium

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