Synthesis, structural characterization, and magnetic property study of {Cr3Ln3}, Ln = Gd and Dy complexes

Abstract

We have successfully prepared and structurally characterized triangle-in-triangle {Cr₃Ln₃} complexes with Ln = Gd and Dy employing alcohol-amine, N-methyldiethanolamine (H₂mdea) and pivalate ligands. These complexes and the Yttrium analogue proved to be isostructural and crystallized in a P₁ triclinic cell. DC and AC magnetic measurements were carried out and supported by quantum computations at DFT and CASSCF levels. DC magnetic data are dominated by the Cr(III)–Ln(III) antiferromagnetic interaction and by single-ion anisotropy in the case of the Dy(III) complex. Ln(III)–Ln(III) magnetic interactions are negligible, as well as Cr(III)–Cr(III) ones. From AC data, slow relaxation of the magnetization is observed at 0 DC applied magnetic field in the case of the Dy(III) complex below 4 K. From temperature and field dependence data, possible Raman and Orbach relaxation mechanisms are established in the absence of quantum tunnelling pathways, suggesting a successful suppression of the latter due to the Cr(III)–Dy(III) exchange interaction.