Mononuclear Lanthanide Complexes with 18-Crown-6 Ether: Synthesis, Characterization, Magnetic Properties, and Theoretical Studies

Lindley Maxwell; Martín Amoza; Eliseo Ruiz

doi:10.1021/acs.inorgchem.8b01688

Mononuclear Lanthanide Complexes with 18-Crown-6 Ether: Synthesis, Characterization, Magnetic Properties, and Theoretical Studies

Inorg Chem. 2018 Nov 5;57(21):13225-13234. doi: 10.1021/acs.inorgchem.8b01688. Epub 2018 Oct 25.

Authors

Lindley Maxwell^{1

2}, Martín Amoza¹, Eliseo Ruiz¹

Affiliations

¹ Departament de Química Inorgànica i Orgànica and Institut de Recerca de Química Teòrica i Computacional , Universitat de Barcelona , Diagonal 645 , E-08028 Barcelona , Spain.
² Advanced Lithium and Industrial Minerals Research Center , Universidad de Antofagasta , Avenida Universidad de Antofagasta , 02800 Antofagasta , Chile.

PMID: 30358999
DOI: 10.1021/acs.inorgchem.8b01688

Abstract

A family of lanthanide metal complexes with the general formula [Ln(H₂O)₃(18-crown-6)](ClO₄)₃ (Ln = Tb^III, Dy^III, Er^III, and Yb^III) has been synthesized. Their magnetic properties have been characterized by direct- and alternating-current SQUID measurements and analyzed with the help of CASSCF-type calculations. The Dy^III and Yb^III compounds show slow relaxation of magnetization under an external magnetic field. Analysis of the dependence of the relaxation time with the temperature and external magnetic field reveals that the main contributions are the quantum tunneling and Raman relaxation terms, respectively. Analysis of the β electron density and electrostatic potentials indicates that the axial ligands (three water molecules) generate a relatively small repulsion, with the lanthanide electron density being the reason for the moderate magnetic anisotropy found in these systems.