Auto-oxidation of the tris-(1,10-phenanthroline)iron(<scp>II</scp>) and tris-(2,2′-bipyridyl)iron(<scp>II</scp>) cations in aqueous sodium hydroxide

Nord, Gwyneth; Pizzino, T.

doi:10.1039/c2970001633b

Cited by 4 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One approach uses organic solvents rather than water, because kinetic behaviour can be less ambiguous in aprotic solvents. In dimethylsulphoxide (DMSO) poorly nucleophilic anions accelerate (14) dissociation in acid that is quantitatively consistent with an ion-pairing mechanism. Similar equilibria were used to explain unusual reactivity patterns in aqueous media (~ 6).…”

Section: Introductionmentioning

confidence: 95%

Kinetics and thermodynamics of solvolysis of tris-(2,2?-bipyridine)-iron(II) perchlorate in dimethylsulphoxide

Twigg¹

1993

Transition Met Chem

View full text Add to dashboard Cite

Diluting a concentrated solution of [-Fe(bipy)3](CtO4) 2 in DMSO causes the complex to dissociate. First order kinetics have been followed, with activation parameters of AH ~ = 26.69 + 0.39 kcal mol-~ and AS ~ = 17.1 + 1.3 cal K-1 mol-1. Comparing rate data in neutral DMSO with those in the presence of acid provides information about the reactivity of the first formed monodentate intermediate. This is more likely to dissociate to [Fe(bipy)2-(DMSO)2] 2+ than undergo ring closure and reform the parent complex than in water. In DMSO, in the presence of added 2,2'-bipyridine at 30.0 ~ C, dissociation is not complete. The reaction is first order, and rate constants increase linearly with added ligand due to an increasingly significant back reaction. Kinetic and static derived values for the third formation constant of [Fe(bipy)3 ] z + agree well, and are smaller than in water. The origins of the reactivity differences in the two solvents are discussed.

show abstract

Section: Introductionmentioning

confidence: 95%

Kinetics and thermodynamics of solvolysis of tris-(2,2?-bipyridine)-iron(II) perchlorate in dimethylsulphoxide

Twigg¹

1993

Transition Met Chem

View full text Add to dashboard Cite

show abstract

“…___ centration is, like the corresponding plots for this complex in acid solution and for Fe(terpy)P [ l l ] , a gentle curve whose tangent increases as the hydroxide ion concentration increases. The reaction of low-spin iron( 11) complexes with hydroxide ion generalyy proceeds by parallel reaction paths of rate-determining dissociation followed by rapid scavenging of iron(I1) species thus produced and of rate-determining nucleophilic attack of hydroxide at the iron(I1) in the complex [ 171; in the presence of oxygen the iron is eventually oxidized to iron(II1) species [18]. Such a reaction scheme corresponds to a linear dependence of observed first-order rate constants on hydroxide ion concentration (large excess) ; our observation of a curved dependence suggests that the reaction of Fe(hxsb)2+, as of Fe(terpy)?…”

Section: V B Reaction With Hydroxidementioning

confidence: 99%

Kinetics of reactions of Schiff base complexes of iron(II). V. Reactions of the complex of the hexadentate ligand NN‴‐bis‐[α‐(2‐pyridyl)benzylidene]triethylenetetramine in acid solution and with hydroxide, cyanide, and peroxodisulphate

Gardner

Mekhail

Burgess

1974

Int J of Chemical Kinetics

View full text Add to dashboard Cite

The preparation and characterization of the iron(I1) complex of the hexadentate Schiff base ligand NN"'-bis-[cr-(2-pyridyl)benzylidene]triethylenetetramine are reported. Kinetic patterns and rate constants for aquation of this complex, and for its reactions with hydroxide, cyanide, and peroxodisulphate have been determined. Activation parameters for the reaction with cyanide, in aqueous solution, are AH: = 24.3 kcal/mole and AS: = + 1 cal/deg-mole.

show abstract

Contribution to the Chemistry of the Belousov−Zhabotinsky Reaction. Products of the Ferriin−Bromomalonic Acid and the Ferriin−Malonic Acid Reactions

Hegedűs

Försterling

Onel³

et al. 2006

J. Phys. Chem. A

View full text Add to dashboard Cite

In the present mechanistic schemes of the ferroin-catalyzed oscillatory Belousov-Zhabotinsky (BZ) reaction the oxidation of the organic substrates (bromomalonic or malonic acid) by ferriin (the oxidized form of the catalyst) plays an important role. As the organic products of these reactions were not yet identified experimentally, they were studied here by an HPLC technique. It was found that the main organic oxidation product of bromomalonic acid is bromo-ethene-tricarboxylic acid (BrEETRA), the same compound that is formed when bromomalonic acid is oxidized by Ce4+ (another catalyst of the BZ reaction). Formation of BrEETRA is explained here by a new mechanism that is more realistic than the one suggested earlier. To find any oxidation product of malonic acid in the ferriin-malonic acid reaction was not successful, however. Neither ethane-tetracarboxylic acid (ETA) nor malonyl malonate (MAMA), the usual products of the Ce4+- malonic acid reaction, nor any other organic acid, not even CO2, was found as a product of the reaction. We propose that malonic acid is not oxidized in the ferriin-malonic acid reaction, and it plays only the role of a complex forming catalyst in a process where Fe3+ oxidizes mostly its phenantroline ligand.

show abstract

Auto-oxidation of the tris-(1,10-phenanthroline)iron(II) and tris-(2,2′-bipyridyl)iron(II) cations in aqueous sodium hydroxide

Abstract: Suunwzary Oxygen is necessary for the rapid reactions of the tris-( l,lO-phenanthroline)iron(II) and of the tris-(2,2'-bipyridyl) iron( 11) cations in aqueous sodium hydroxide.

Cited by 4 publications

References 0 publications

Kinetics and thermodynamics of solvolysis of tris-(2,2?-bipyridine)-iron(II) perchlorate in dimethylsulphoxide

Kinetics and thermodynamics of solvolysis of tris-(2,2?-bipyridine)-iron(II) perchlorate in dimethylsulphoxide

Kinetics of reactions of Schiff base complexes of iron(II). V. Reactions of the complex of the hexadentate ligand NN‴‐bis‐[α‐(2‐pyridyl)benzylidene]triethylenetetramine in acid solution and with hydroxide, cyanide, and peroxodisulphate

Contribution to the Chemistry of the Belousov−Zhabotinsky Reaction. Products of the Ferriin−Bromomalonic Acid and the Ferriin−Malonic Acid Reactions

Contact Info

Product

Resources

About