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Annibale, Giuliano; Brandolisio, Matilde; Bugarčić, Živadin D.; Cattalini, L.

doi:10.1023/a:1006935302166

Cited by 31 publications

(17 citation statements)

References 5 publications

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“…In agreement with the earlier reported results that metalterpyridine complexes do not undergo substitution reactions with thioethers, 42 similar results were obtained in this study. UV-Vis spectra recorded for a tandem reaction of [Au(terpy)-Cl] 2+ and L-Met in the 1 : 100 molar ratio at pH 2.5 and 7 showed that the reaction proceeds really slowly and yields the free terpyridine ligand, see Fig.…”

Section: Reactions With L-methioninesupporting

confidence: 94%

Substitution versus redox reactions of gold(iii) complexes with l-cysteine, l-methionine and glutathione

et al. 2014

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The influence of tridentate, nitrogen donor ligands, on the stability of gold(III) complexes under physiological conditions was investigated. The interaction of [Au(terpy)Cl] 2+ (terpy = 2,2':6'2'' terpyridine), [Au(bpma)Cl] 2+ (bpma = bis(pyridyl-methyl)amine), [Au(dien)Cl] 2+ (dien = diethylenetriamine) and [AuCl 4 ] − with the biologically relevant thiols, L-cysteine (L-Cys) and glutathione (GSH), and thioether, L-methionine (L-Met), was studied using UV-Vis spectroscopy, cyclic voltammetry, 1 H NMR spectroscopy and ESI-MS. In this study, the rate constants for substitution reactions between monofunctional gold(III) complexes and sulfur donor ligands in aqueous solution were determined at different initial concentrations of reactants, chloride ions, pH and constant ionic strength. The obtained second-order rate constants for the reaction with L-methionine in the absence of added chloride at pH 2.5 and 25°C follow the sequence (7.5 ± 0.4) × 10 3 > (4.5 ± 0.1) × 10 2 > 88.3 ± 0.8 M −1 s −1 for the terpy, bpma and dien complexes, respectively, demonstrating that the substitution step could be detected prior to the reduction step. This behavior was expected due to the influence of a decreasing π-donor ability of the chelate ligands, which slows down the substitution reactions along the series of complexes studied. In order to throw more light on the mechanism of biological activity of gold(III) compounds, such a systematic study was performed for all the mentioned thiols and thioether.

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Section: Reactions With L-methioninesupporting

confidence: 94%

Substitution versus redox reactions of gold(iii) complexes with l-cysteine, l-methionine and glutathione

et al. 2014

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“…In order to prevent dimerization and hydrolysis of the complex all reactions were studied in acidic methanol/water (95/5 %,v/v) solution. Under these conditions the complex is stable [12].…”

Section: Resultsmentioning

confidence: 98%

“…[Pt(terpy)Cl] + exists in aqueous solution [12]. In order to prevent dimerization and hydrolysis of the complex all reactions were studied in acidic methanol/water (95/5 %,v/v) solution.…”

Section: Resultsmentioning

confidence: 99%

“…Since the thiols are undissociated in these experiments, this meatLs that the act of substitution is immediately followed by deprot+onation of the products [Pt(terpy)(RSH)] and the reaction leads to the thiolate complex [Pt(terpy)(SR)] which is the final product. In the reaction with L-methionine there is no possibility for the deprotonation and this+could be the main reason for the difference in the reactivity between thiols and thioethers with [Pt(terpy)Cl] It seems, therefore, that thioethers do not react just because the resulting bis-cationic product cannot be stabilized by deprotonation [12]. Therefore, even if there is not any difference in the nucleophilicity of thiols and thioethers, a difference is clearly evident in the relative stability of the reaction products [12].…”

Section: Resultsmentioning

confidence: 99%

“…We recently reported a detailed kinetic and mechanistic study of the complex formation between different platinum(If)complexes and some thiols [10,12,13]. Since interactions between platinum(II) complexes and sulfur-containing ligands are very important from biological and medicinal aspects, in the present paper, we reported a study of the rection between [Pt(terpy)Cl] and some biologically important thiols such as" glutathione, L-cysteine, D-penicillamine and thioglycolic acid.…”

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confidence: 95%

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Binding of Platinum(II) to Some Biologicaly Important Thiols

1999

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The reactions between [Pt(terpy)Cl+ and thiols, such as glutathione, L-cysteine, D-penicillamine and thioglycolic acid have been Studied by conventional UV-VIS spectrophotometry and H NMR spectroscopy. The second-ordero rate constants, K2, are similar for these four thiols, varying between 1.06 x 10-2 and 6.10 x 10+3 M-1 s-1 at 25°C. The activation entropies have large negative values between -100 and -200 J mol-1 which are compatible with an associative A mechanism. However, L-methionine, as thioether ligand, is unreactive under the same experimental conditions. The obtained results have been analyzed in relation to the antitumor activity and toxicity of platinum(II) complexes.

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Kinetic and mechanistic investigation into the influence of chelate substituents on the substitution reactions of platinum(II) terpyridine complexes

Jaganyi

Boer

Gertenbach

et al. 2008

Int J of Chemical Kinetics

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The substitution kinetics of the complexes [Pt{4 -(o -CH 3 -Ph)-terpy} Cl]SbF 6 (CH 3 PhPtCl(Sb)), (ClPhPtCl), and [Pt{4 -(o -CF 3 -Ph)-terpy}Cl]SbF 6 (CF 3 PhPtCl), where terpy is 2,2 :6 ,2 -terpyridine, with the nucleophiles thiourea (TU), N,N -dimethylthiourea (DMTU), and N,N,N ,Ntetramethylthiourea (TMTU) were investigated in methanol as a solvent. The substitution reactions of the chloride displacement from the metal complexes by the nucleophiles were investigated as a function of nucleophile concentration and temperature under pseudo-first-order conditions using the stopped-flow technique. The reactions followed the simple rate law k obs = k 2 [Nu]. The results indicate that the introduction of substituents in the ortho position of the phenyl group on the ancillary ring of the terpy unit does influence the extent of π -backbonding in the terpy ring. This controls the electrophilicity of the platinum center, which in turn controls the lability of the chloro-leaving group. The strength of the electron-donating or -withdrawing ability of the substituents correlates with the reactivity of the complexes. Electron-donating

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Untitled

Cited by 31 publications

References 5 publications

Substitution versus redox reactions of gold(iii) complexes with l-cysteine, l-methionine and glutathione

Substitution versus redox reactions of gold(iii) complexes with l-cysteine, l-methionine and glutathione

Binding of Platinum(II) to Some Biologicaly Important Thiols

Kinetic and mechanistic investigation into the influence of chelate substituents on the substitution reactions of platinum(II) terpyridine complexes

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