Title :

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

Author(s) :

Huittinen, Nina [Auteur]
Institute of Resource Ecology [Dresden] [IRE]
Jessat, Isabelle [Auteur]
Institute of Resource Ecology [Dresden] [IRE]
Réal, Florent [Auteur correspondant]
Physico-Chimie Moléculaire Théorique [PCMT]
Vallet, Valérie [Auteur]
Institute of Resource Ecology [Dresden] [IRE]
Physico-Chimie Moléculaire Théorique [PCMT]
Starke, Sebastian [Auteur]
Eibl, Manuel [Auteur]
Institute of Resource Ecology [Dresden] [IRE]
Jordan, Norbert [Auteur correspondant]
Institute of Resource Ecology [Dresden] [IRE]

Journal title :

Inorganic Chemistry

Pages :

10656-10673

Publisher :

American Chemical Society

Publication date :

2021-07-19

ISSN :

0020-1669

HAL domain(s) :

Chimie/Chimie théorique et/ou physique
Physique [physics]/Physique [physics]/Chimie-Physique [physics.chem-ph]

English abstract : [en]

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<sub>2< ...
Show more >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(H₂PO₄)²⁺, the formation of Cm(H₂PO₄)²⁺ was unambiguously established from the luminescence spectroscopic data collected at various H+ concentrations (−log₁₀ [H⁺] = 2.52, 3.44, and 3.65), ionic strengths (0.5–3.0 mol·L^-1 NaClO₄), 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 &Delta;_RH_m⁰ and molal entropy &Delta;_RS_m⁰ of both complexation reactions were derived using the integrated van’t Hoff equation and indicated an endothermic and entropy-driven complexation. For the Cm(H₂PO₄)²⁺ complex, a more satisfactory description could be obtained when including the molal heat capacity term. While monodentate binding of the H₂PO₄^- 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 temperature-dependent coordination to hydration water molecules could be deduced from the electronic structure of the Cm(III)–phosphate complexes. More precisely, where the Cm(H₂PO₄)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(H₂PO₄)²⁺ species with increasing temperature.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

ANR Project :

Physiques et Chimie de l'Environnement Atmosphérique
ULNE

Collections :

• Laboratoire de Physique des Lasers, Atomes et Molécules (PhLAM) - UMR 8523

Source :

Harvested from HAL