pH-static titrations for kinetic studies of metal-ligand complex formation: The case example of the reaction between Strontium(II) and DOTA

Marco, Valerio Di; Pastore, Paolo; Tosato, Marianna; Andrighetto, A.; Borgna, Francesca; Realdon, Nicola

doi:10.1016/j.ica.2019.119147

Cited by 4 publications

(6 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The lower reaction rate at the more acidic pH is ascribed to the increase of the electrostatic repulsion between the metal ion and the protons on the donor sites, which become progressively more protonated (secondary amines of the macrocycle and acetate groups of the side arms). 20 − 22 …”

Section: Results and Discussionmentioning

confidence: 99%

“…The constants for ligand deprotonation and Pb 2+ hydrolysis were taken from the literature. 20,28 Pb 2+ -DOTA Dissociation Kinetics. The dissociation kinetics of the Pb 2+ -DOTA complex was studied under pseudo-first-order conditions in an aqueous solution at room temperature without control of the ionic strength by adding concentrated aqueous solutions of HCl (0.01, 0.1, and 1 M) to aqueous solutions of the preformed complex.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…On the other hand, at a concentration of 10 –3 M, the complexation reaction reached equilibrium in ∼10 min at pH 2 and became instantaneous at pH 4.5 (Figure S2). The lower reaction rate at the more acidic pH is ascribed to the increase of the electrostatic repulsion between the metal ion and the protons on the donor sites, which become progressively more protonated (secondary amines of the macrocycle and acetate groups of the side arms). − …”

Section: Results and Discussionmentioning

confidence: 99%

“…Unless otherwise stated, the reported data are referred to T = 298 K. b L denotes DOTA in its fully deprotonated form. c From ref ( 20 ), I = 0.15 M NaCl. d From ref ( 18 ), I = 0.1 M Me 4 NNO 3 .…”

Section: Introductionmentioning

confidence: 99%

“… a Literature data are reported for comparison. Unless otherwise stated, the reported data are referred to T = 298 K. b L denotes DOTA in its fully deprotonated form. c From ref , I = 0.15 M NaCl. d From ref , I = 0.1 M Me 4 NNO 3 . The method was potentiometry. e From ref , I = 0.1 M NMe 4 Cl. f The reported uncertainty was obtained via the fitting procedure and represents one standard deviation unit. g From ref , I = 0.1 M NaClO 4 .…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Revisiting Lead(II)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic Acid Coordination Chemistry in Aqueous Solutions: Evidence of an Underestimated Thermodynamic Stability

2022

View full text Add to dashboard Cite

The complexes formed between Pb 2+ and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) were reinvestigated in aqueous solutions using a combination of pH potentiometry, UV–vis spectroscopy, and NMR spectroscopy. The thermodynamic data were supported by kinetics assays. Differently protonated complexes, i.e ., [PbH 3 L] + , [PbH 2 L], [PbHL] − , and [PbL] 2– , were detected, and the corresponding stability constants (log β ) at T = 298 K and I = 0.1 M NaCl were 33.1 ± 0.2, 32.00 ± 0.06, 29.28 ± 0.06, and 25.3 ± 0.1, respectively. Results differed significantly from those previously reported by Chaves et al. ( 18965370 Talanta 1992 39 249 ) and Pippin et al. ( Inorg. Chim. Acta 1995 239 43 ) in both the speciation and the overall complex stability; the latter in particular was found to be remarkably higher. The work disclosed herein provides revised data on the Pb 2+ -DOTA complexes, which should be used as a new stability benchmark during the development of lead chelators.

show abstract

Section: Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%