Investigation of equilibria in solution. Determination of equilibrium constants with the HYPERQUAD suite of programs

Gans, Paul; Sabatini, A.; Vacca, Alberto

doi:10.1016/0039-9140(96)01958-3

Cited by 3,109 publications

(2,956 citation statements)

References 56 publications

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“…1 HYPERQUAD was used to calculate the deprotonation constants from the titration data. 27 Species diagrams were computed using a program based on the COMICS algorithm. 28 Kinetic Measurements.…”

Section: Dinitrophenyl) Phosphate (Bdnpp) Coordination Of the Tetradmentioning

confidence: 99%

Ga^III Complexes as Models for the M^III Site of Purple Acid Phosphatase: Ligand Effects on the Hydrolytic Reactivity Toward Bis(2,4-dinitrophenyl) phosphate

2010

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The effects of a series of Ga III complexes with tripodal ligands on the hydrolysis rate of the activated phosphate diester bis(2,4-dinitrophenyl)phosphate (BDNPP) have been investigated. In particular, the influence of the nature of the ligand donor sites on the reactivity of Ga III which represents a mimic of the Fe III ion in purple acid phosphatase has been evaluated. It has been shown that replacing neutral nitrogen donor atoms and carboxylate groups by phenolate groups enhanced the reactivity of the Ga complexes. Bell-shaped pH-rate profiles and the measured solvent deuterium isotope effects are indicative of a mechanism that involves nucleophilic attack on the coordinated substrate by Ga-OH. The trend in reactivity found for the different Ga complexes reveals that of the two effects of the metal, Lewis acid activation of the substrate and nucleophile activation, the latter one is more important in determining the intrinsic reactivity of the metal catalyst. The relevance of the present findings for the modulation of the activity of the M III ion in purple acid phosphatase whose active site contains a phenolate (tyrosine side chain) is discussed.

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Section: Dinitrophenyl) Phosphate (Bdnpp) Coordination Of the Tetradmentioning

confidence: 99%

Ga^III Complexes as Models for the M^III Site of Purple Acid Phosphatase: Ligand Effects on the Hydrolytic Reactivity Toward Bis(2,4-dinitrophenyl) phosphate

2010

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“…Usually 25 -30 additions were made, thus generating a set of 25 -30 spectra in each titration. The stability constants of the U(VI)/fluoride complexes (on the molarity scale) were calculated by non-linear least-square regression using the Hyperquad program [9].…”

Section: Spectrophotometrymentioning

confidence: 99%

Effect of Temperature on the Complexation of Uranium(VI) with Fluoride in Aqueous Solutions

Tian

Rao

2009

Inorg. Chem.

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“…Low pH titrations were performed from pH 3 down to pH 1.6, and electrodes were calibrated as described in a previous publication. [47] Titration Data Treatment: Potentiometric data were analyzed using Hyperquad [48,49] software. The data from at least three independent titrations, each consisting of one forward (pH 3 to pH 10) and one reverse (pH 10 to pH 3) titration were analyzed separately.…”

Section: Spectrophotometric and Potentiometric Titrationsmentioning

confidence: 99%

The Influence of Linker Geometry in Bis(3‐hydroxy‐N‐methyl‐pyridin‐2‐one) Ligands on Solution Phase Uranyl Affinity

Szigethy

Raymond

2011

Chemistry A European J

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Seven water‐soluble, tetradentate bis(3‐hydroxy‐N‐methyl‐pyridin‐2‐one) (bis‐Me‐3,2‐HOPO) ligands were synthesized that vary only in linker geometry and rigidity. Solution‐phase thermodynamic measurements were conducted between pH 1.6 and pH 9.0 to determine the effects of these variations on proton and uranyl cation affinity. Proton affinity decreases by introduction of the solubilizing triethylene glycol group as compared to unsubstituted reference ligands. Uranyl affinity was found to follow no discernable trends with incremental geometric modification. The butyl‐linked 4 li‐Me‐3,2‐HOPO ligand exhibited the highest uranyl affinity, consistent with prior in vivo decorporation results. Of the rigidly‐linked ligands, the o‐phenylene linker imparted the best uranyl affinity to the bis‐Me‐3,2‐HOPO ligand platform.

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Investigation of equilibria in solution. Determination of equilibrium constants with the HYPERQUAD suite of programs

Cited by 3,109 publications

References 56 publications

Ga^III Complexes as Models for the M^III Site of Purple Acid Phosphatase: Ligand Effects on the Hydrolytic Reactivity Toward Bis(2,4-dinitrophenyl) phosphate

Ga^III Complexes as Models for the M^III Site of Purple Acid Phosphatase: Ligand Effects on the Hydrolytic Reactivity Toward Bis(2,4-dinitrophenyl) phosphate

Effect of Temperature on the Complexation of Uranium(VI) with Fluoride in Aqueous Solutions

The Influence of Linker Geometry in Bis(3‐hydroxy‐N‐methyl‐pyridin‐2‐one) Ligands on Solution Phase Uranyl Affinity

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Investigation of equilibria in solution. Determination of equilibrium constants with the HYPERQUAD suite of programs

Cited by 3,109 publications

References 56 publications

GaIII Complexes as Models for the MIII Site of Purple Acid Phosphatase: Ligand Effects on the Hydrolytic Reactivity Toward Bis(2,4-dinitrophenyl) phosphate

GaIII Complexes as Models for the MIII Site of Purple Acid Phosphatase: Ligand Effects on the Hydrolytic Reactivity Toward Bis(2,4-dinitrophenyl) phosphate

Effect of Temperature on the Complexation of Uranium(VI) with Fluoride in Aqueous Solutions

The Influence of Linker Geometry in Bis(3‐hydroxy‐N‐methyl‐pyridin‐2‐one) Ligands on Solution Phase Uranyl Affinity

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Ga^III Complexes as Models for the M^III Site of Purple Acid Phosphatase: Ligand Effects on the Hydrolytic Reactivity Toward Bis(2,4-dinitrophenyl) phosphate

Ga^III Complexes as Models for the M^III Site of Purple Acid Phosphatase: Ligand Effects on the Hydrolytic Reactivity Toward Bis(2,4-dinitrophenyl) phosphate