Stability constants for Zirconium(IV) complexes with EDTA, CDTA, and DTPA in perchloric acid solutions

Friend, Mitchell T.; Wall, Nathalie A.

doi:10.1016/j.ica.2018.09.034

Cited by 16 publications

(5 citation statements)

References 32 publications

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“…In total, optimized structures and reaction energetics for 23 different Zr 4+ complexes, using 17 different ligands (Figure ), were calculated. ,,,− Structures of the optimized Zr complexes are presented in Figure , and key thermodynamic data are given in Table . The ligands chosen were selected on the basis of their reported experimental potential to form stable complexes with 89 Zr 4+ ions and also on the basis of their availability as bifunctional versions that can be coupled to protein.…”

Section: Results and Discussionmentioning

confidence: 99%

“…In total, optimised structures and reaction energetics for 23 different Zr 4+ complexes, using 17 different ligands (Figure 11) were calculated. 2,10,38,[46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] Structures of the optimised Zr-complexes are presented in Figure 12 and key thermodynamic data are given in Table 2. The ligands chosen were selected based on their reported experimental potential to form stable complexes with 89 Zr 4+…”

Section: Predicting the Absolute And Relative Formation Constants Of Zirconium Complexesmentioning

confidence: 99%

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Predicting the Thermodynamic Stability of Zirconium Radiotracers

Holland

2020

Inorg. Chem.

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The thermodynamic stability of a metal−ligand complex, as measured by the formation constant (log), is one of themost important parameters that determines metal ion selectivity and potential applications in, for example, radiopharmaceuticalscience. The stable coordination chemistry of radioactive89Zr4+in an aqueous environment is of paramount importance whendeveloping positronemitting radiotracers based on proteins (usually antibodies) for use with positron emission tomography.Desferrioxamine B (DFO) remains the chelate of choice for clinical applications of89Zr-labeled proteins, but the coordination ofDFO to Zr4+ions is suboptimal. Many alternative ligands have been reported, but the challenges in measuring very high logvalueswith metal ions such as Zr4+that tend to hydrolyze mean that accurate thermodynamic data are scarce. In this work, densityfunctional theory (DFT) calculations were used to predict the reaction energetics for metal ion complexation. Computed values ofpseudoformation constants (log) are correlated with experimental data and showed an excellent linear relationship (R2= 0.97).The model was then used to estimate the absolute and relative formation constants of 23 different Zr4+complexes using a total of 17different ligands, including many of the alternative bifunctional chelates that have been reported recently for use in89Zr4+radiochemistry. In addition, detailed computational studies were performed on the geometric isomerism and hydration state of Zrdesferrioxamine. Collectively, the results offer new insights into Zr4+coordination chemistry that will help guide the synthesis offuture ligands. The computational model developed here is straightforward and reproducible and can be readily applied in the designof other metal coordination compounds.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Predicting the Absolute And Relative Formation Constants Of Zirconium Complexesmentioning

confidence: 99%

Predicting the Thermodynamic Stability of Zirconium Radiotracers

Holland

2020

Inorg. Chem.

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“…Cluster topologies that self-assemble in aqueous Zr/Hf solutions are limited in scope. The Zr/Hf clusters include tetrameric and hexameric forms; the former is ubiquitous in aqueous hydrohalic acid and uncertain in perchloric acid solution. , The Clearfield–Vaughan tetramer ( Zr 4 ), dubbed as such in reference to its initial isolation, − is an acidic polycation formulated [Zr 4 (OH) 8 (H 2 O) 16 ] 8+ (Figure ), commonly described and sold commercially as “ZrOCl 2 ·8H 2 O”. The hexamer topology, consisting of a Zr 6 (O,OH) 8 core with antiprismatic-Zr polyhedra arranged in a pseudo-octahedron, presumably requires a bridging ligand to convert Zr 4 to Zr 6 in water .…”

Section: Introductionmentioning

confidence: 99%

Peroxide-Promoted Disassembly Reassembly of Zr-Polyoxocations

et al. 2019

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Zr/Hf aqueous-acid clusters are relevant to inorganic nanolithography, metal−organic frameworks (MOFs), catalysis, and nuclear fuel reprocessing, but only two topologies have been identified. The (Zr 4 ) polyoxocation is the ubiquitous square aqueous Zr/Hfoxysalt of all halides (except fluoride), and prior-debated for perchlorate. Simply adding peroxide to a Zr oxyperchlorate solution leads to a striking modification of Zr 4 , yielding two structures identified by single-crystal X-ray diffraction. Zr 25 , isolated from a reaction solution of 1:1 peroxide/Zr, is fully formulatedZr 25 is a pentagonal assembly of 25 Zr-oxy/peroxo/ hydroxyl polyhedra and is the largest Zr/Hf cluster topology identified to date. Yet it is completely soluble in common organic solvents. ZrT d , an oxo-centered tetrahedron fully formulated [Zr 4 (OH) is isolated from a 10:1 peroxide/Zr reaction solution. The formation pathways of ZrT d and Zr 25 in water were described by small-angle X-ray scattering (SAXS), pair distribution function (PDF), and electrospray ionization mass spectrometry (ESI-MS). Zr 4 undergoes disassembly by 1 equiv of peroxide (per Zr) to yield small oligomers of Zr 25 that assemble predominantly in the solid state, an unusual crystal growth mechanism. The self-buffering acidity of the Zr-center prevents Zr 25 from remaining intact in water. Identical species distribution and cluster fragments are observed in the assembly of Zr 25 and upon redissolution of Zr 25 . On the other hand, the 10:1 peroxide/Zr ratio of the ZrT d reaction solution yields larger prenucleation clusters before undergoing peroxide-promote disassembly into smaller fragments. Neither these larger cluster intermediates of ZrT d nor the smaller intermediates of Zr 25 have yet been isolated and structurally characterized, and they represent an opportunity to expand this new class of group IV polycations, obtained by peroxide reactivity and ligation.

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“…Since iTLC-SG/50 mM DTPA pH 7.0 system is most often mentioned in the literature for analyzing [ 89 Zr]Zr-radiopharmaceutical preparations ([ 89 Zr]Zr-DFO and [ 89 Zr]Zr-DFO-mAb—R f = 0; unbound zirconium-89—R f = 1) [32,47,53,54,55,56,57,58], we decided to use this system (further referred to as Method 1 ) as a control in all experiments. In addition, according to literature data, zirconium forms more stable complexes with DTPA than those with EDTA (stability constants for [Zr(EDTA)] 0 , [Zr(EDTA) 2 ] 4− , [Zr(DTPA)] − and [ZrH 8 (DTPA) 2 ] 2+ are 27.9 ± 0.1, 54.4 ± 0.2, 35.3 ± 0.3 and 70.3 ± 0.4, correspondingly [59]).…”

Section: Resultsmentioning

confidence: 99%

Preparation of Zirconium-89 Solutions for Radiopharmaceutical Purposes: Interrelation Between Formulation, Radiochemical Purity, Stability and Biodistribution

et al. 2019

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Zirconium-89 is a promising radionuclide for nuclear medicine. The aim of the present work was to find a suitable method for obtaining zirconium-89 solutions for radiopharmaceutical purposes. For this purpose, the ion exchange behavior of zirconium-89 solutions was studied. Radio-TLC (thin layer chromatography) and biodistribution studies were carried out to understand speciation of zirconium-89 complexes and their role in the development of new radiopharmaceuticals. Three methods of zirconium-89 isolation were studied using ZR (hydroxamate) and Chelex-100 resins. It was found that ZR-resin alone is not enough to obtain stable zirconium-89 formulations. An easy and effective method of reconstitution of [89Zr]Zr-oxalate to [89Zr]Zr-citrate using Chelex-100 resin was developed. Developed procedures allow obtaining [89Zr]Zr-oxalate (in 0.1 M sodium oxalate solution) and [89Zr]Zr-citrate (in 0.1–1.0 M sodium citrate solution). These solutions are perfectly suitable and convenient for radiopharmaceutical purposes. Our results prove [89Zr]Zr-citrate to be advantageous over [89Zr]Zr-oxalate. During evaluation of speciation of zirconium-89 complexes, a new TLC method was developed, since it was proved that there is no comprehensive method for analysis or zirconium-89 preparations. The new method provides valuable insights about the content of “active” ionic form of zirconium-89. The interrelation of the chromatographic behavior of zirconium-89 preparations and their biodistribution was studied.

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Stability constants for Zirconium(IV) complexes with EDTA, CDTA, and DTPA in perchloric acid solutions

Cited by 16 publications

References 32 publications

Predicting the Thermodynamic Stability of Zirconium Radiotracers

Predicting the Thermodynamic Stability of Zirconium Radiotracers

Peroxide-Promoted Disassembly Reassembly of Zr-Polyoxocations

Preparation of Zirconium-89 Solutions for Radiopharmaceutical Purposes: Interrelation Between Formulation, Radiochemical Purity, Stability and Biodistribution

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