How Does CeIIINitrate Dissolve in a Protic Ionic Liquid? A Combined Molecular Dynamics and EXAFS Study.
A diluted solution of Ce(NO3)3in the protic ionic liquid (IL) ethylammonium nitrate (EAN) was investigated using molecular dynamics (MD) simulations and extended X-ray absorption fine structure (EXAFS) spectroscopy. For the first time polarizable effects were included in the MD force field to describe a heavy metal ion in a protic IL, but, unlike water, they were found to be unessential. The CeIIIion first solvation shell is formed by nitrate ions arranged in an icosahedral structure, and an equilibrium between monodentate and bidentate ligands is present in the solution. By combining distance and angular distribution functions it was possible to unambiguously identify this peculiar coordination geometry around the ions dissolved in solution. The metal ions are solvated within the polar domains of the EAN nanostructure and the dissolved salt induces almost no reorganization of the pre-existing structure of EAN upon solubilization.
Dipartimento di Chimica, Università di Roma "La Sapienza", P. le A. Moro 5, 00185, Roma, Italy.
Alessandra
http://orcid.org/0000-0002-7525-2494
A
Serva
Dipartimento di Chimica, Università di Roma "La Sapienza", P. le A. Moro 5, 00185, Roma, Italy.
Valentina
http://orcid.org/0000-0003-4733-6188
V
Migliorati
LAMBE CEA, CNRS, Université Paris Saclay, 91025, Evry Cedex, France.|LAMBE Université d'Evry, 91025, Evry Cedex, France.
Riccardo
http://orcid.org/0000-0001-5160-489X
R
Spezia
Dipartimento di Chimica, Università di Roma "La Sapienza", P. le A. Moro 5, 00185, Roma, Italy.
Paola
http://orcid.org/0000-0001-5015-8410
P
D'Angelo
EXAFS spectroscopy; ethylammonium nitrate; icosahedral structure; lanthanoid ions; molecular dynamics