Lanthanide-based organic salts: Synthesis, characterization, and cytotoxicity studies

This work was supported by Fundação para a Ciência e a Tecnologia through projects (PEst-C/LA0006/2013, PTCD/CTM-NAN/120658/2010, two contracts under Investigador FCT (L. C. Branco and I. M. Marrucho), a doctoral fellowship Andreia Forte (PD/BD/109625/2015), and by the Portuguese Foundation for Science and Technology (FCT) through the strategic project UID/MAR/04292/2020 granted to MARE—Marine and Environmental Sciences Centre and Solchemar company.The formulation of magnetic ionic liquids (MILs) or organic salts based on lanthanides as anions has been explored. In this work, a set of choline-family-based salts, and two other, different cation families, were combined with Gadolinium(III) and Terbium(III) anions. Synthetic methodologies were previously optimized, and all organic salts were obtained as solids with melting temperatures higher than 100 °C. The magnetic moments obtained for the Gd(III) salts were, as expected, smaller than those obtained for the Tb(III)-based compounds. The values for Gd(III) and Tb(III) magnetic salts are in the range of 6.55–7.30 MB and 8.22–9.34 MB, respectively. It is important to note a correlation between the magnetic moments obtained for lanthanides, and the structural features of the cation. The cytotoxicity of lanthanide-based salts was also evaluated using 3T3, 293T, Caco2, and HepG2 cells, and it was revealed that most of the prepared compounds are not toxic.