Complexation of Trivalent Lanthanides (Eu) and Actinides (Cm) with Aqueous Phosphates at Elevated Temperatures

Jordan, Norbert; Demnitz, Maximilian; Lösch, Henry; Starke, Sebastian; Brendler, Vinzenz; Huittinen, Nina

doi:10.1021/acs.inorgchem.8b00647

Cited by 20 publications

(25 citation statements)

References 30 publications

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“…This is especially troublesome when studying redox reactions. Phosphate ions are known to readily precipitate supplemented lanthanides [37]. Tris(hydroxymethyl)-aminomethane buffer (Tris) is strongly temperature dependent and can further undergo Schiff base-type condensations with aldehydes, which is problematic when investigating substrates like formaldehyde [38,39].…”

Section: The Redox Dye Dcpipmentioning

confidence: 99%

Understanding the chemistry of the artificial electron acceptors PES, PMS, DCPIP and Wurster’s Blue in methanol dehydrogenase assays

Jahn

Jonasson

et al. 2020

J Biol Inorg Chem

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Methanol dehydrogenases (MDH) have recently taken the spotlight with the discovery that a large portion of these enzymes in nature utilize lanthanides in their active sites. The kinetic parameters of these enzymes are determined with a spectrophotometric assay first described by Anthony and Zatman 55 years ago. This artificial assay uses alkylated phenazines, such as phenazine ethosulfate (PES) or phenazine methosulfate (PMS), as primary electron acceptors (EAs) and the electron transfer is further coupled to a dye. However, many groups have reported problems concerning the bleaching of the assay mixture in the absence of MDH and the reproducibility of those assays. Hence, the comparison of kinetic data among MDH enzymes of different species is often cumbersome. Using mass spectrometry, UV-Vis and electron paramagnetic resonance (EPR) spectroscopy, we show that the side reactions of the assay mixture are mainly due to the degradation of assay components. Light-induced demethylation (yielding formaldehyde and phenazine in the case of PMS) or oxidation of PES or PMS as well as a reaction with assay components (ammonia, cyanide) can occur. We suggest here a protocol to avoid these side reactions. Further, we describe a modified synthesis protocol for obtaining the alternative electron acceptor, Wurster's blue (WB), which serves both as EA and dye. The investigation of two lanthanide-dependent methanol dehydrogenases from Methylorubrum extorquens AM1 and Methylacidiphilum fumariolicum SolV with WB, along with handling recommendations, is presented.

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Section: The Redox Dye Dcpipmentioning

confidence: 99%

Understanding the chemistry of the artificial electron acceptors PES, PMS, DCPIP and Wurster’s Blue in methanol dehydrogenase assays

Jahn

Jonasson

et al. 2020

J Biol Inorg Chem

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“… b Recalculated using the values published by Jordan et al and the log 10 β 0 and Δ R H m 0 values for the reaction H + + H 2 PO 4 – ⇌ H 3 PO 4 at each temperature from Grenthe et al …”

Section: Introductionmentioning

confidence: 92%

“…As already recognized in our previous investigation dealing with the complexation of Eu(III) and Cm(III) with aqueous phosphates at elevated temperatures, studies concerning the complexation reactions of trivalent actinides with various phosphate ligands, i . e ., H 2 PO 4 – , HPO 4 2– , or PO 4 3– , are rather scarce.…”

Section: Introductionmentioning

confidence: 99%

“… a TRLFS: time-resolved laser-induced fluorescence spectroscopy. b Recalculated using the values published by Jordan et al and the log 10 β 0 and Δ R H m 0 values for the reaction H + + H 2 PO 4 – ⇌ H 3 PO 4 at each temperature from Grenthe et al c R.T. : room temperature. d From the value recalculated by Moll et al for the equilibrium Cm 3+ + 2H + + PO 4 3– ⇌ Cm(H 2 PO 4 ) 2+ . e N.A.…”

Section: Introductionmentioning

confidence: 99%

“…For the Am(H 2 PO 4 ) 2+ complex, Silva et al (Nuclear Energy Agency (NEA) Thermochemical Database (TDB) Project, vol. 2) recommended a log 10 β° value at 25 °C, based on the solvent extraction study of Rao et al Later Morgenstern and Moll et al reported a log 10 β° value of very similar magnitude for Cm(H 2 PO 4 ) 2+ , derived from luminescence spectroscopic investigations, which has been recently confirmed . The latest volume of the NEA-TDB recommends a log 10 β° value for Cm(H 2 PO 4 ) 2+ based on the study of Moll et al and assumes this value to be a good approximation for Am(H 2 PO 4 ) 2+ .…”

Section: Introductionmentioning

confidence: 99%

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Revisiting the Complexation of Cm(III) with Aqueous Phosphates: What Can We Learn from the Complex Structures Using Luminescence Spectroscopy and Ab Initio Simulations?

et al. 2021

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The coordination chemistry of Cm(III) with aqueous phosphates was investigated by means of laser-induced luminescence spectroscopy and ab initio simulations. For the first time, in addition to the presence of Cm(H 2 PO 4 ) 2+ , the formation of Cm(H 2 PO 4 ) 2 + was unambiguously established from the luminescence spectroscopic data collected at various H + concentrations (−log 10 [H + ] = 2.52, 3.44, and 3.65), ionic strengths (0.5−3.0 mol•L −1 NaClO 4 ), and temperatures (25−90 °C). Complexation constants for both species were derived and extrapolated to standard conditions using the specific ion interaction theory. The molal enthalpy Δ R H m 0 and molal entropy Δ R S m 0 of both complexation reactions were derived using the integrated van't Hoff equation and indicated an endothermic and entropy-driven complexation. For the Cm(H 2 PO 4 ) 2 + complex, a more satisfactory description could be obtained when including the molal heat capacity term. While monodentate binding of the H 2 PO 4 − ligand(s) to the central curium ion was found to be the most stable configuration for both complexes in our ab initio simulations and luminescence lifetime analyses, a different temperaturedependent coordination to hydration water molecules could be deduced from the electronic structure of the Cm(III)−phosphate complexes. More precisely, where the Cm(H 2 PO 4 ) 2+ complex could be shown to retain an overall coordination number of 9 over the entire investigated temperature range, a coordination change from 9 to 8 was established for the Cm(H 2 PO 4 ) 2 + species with increasing temperature.

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Association of Eu(III) and Cm(III) onto an extremely halophilic archaeon

Bader

Moll

Steudtner

et al. 2019

Environ Sci Pollut Res

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Complexation of Trivalent Lanthanides (Eu) and Actinides (Cm) with Aqueous Phosphates at Elevated Temperatures

Cited by 20 publications

References 30 publications

Understanding the chemistry of the artificial electron acceptors PES, PMS, DCPIP and Wurster’s Blue in methanol dehydrogenase assays

Understanding the chemistry of the artificial electron acceptors PES, PMS, DCPIP and Wurster’s Blue in methanol dehydrogenase assays

Revisiting the Complexation of Cm(III) with Aqueous Phosphates: What Can We Learn from the Complex Structures Using Luminescence Spectroscopy and Ab Initio Simulations?

Association of Eu(III) and Cm(III) onto an extremely halophilic archaeon

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