Effect of Ligand Substitution on Zero-Field Slow Magnetic Relaxation in Mononuclear Dy(III) ?-Diketonate Complexes with Phenanthroline-Based Ligands

Herein, we report the synthesis, structure and magnetic properties of two mononuclear complexes general formula [Dy(acac)3(L)], where L = 2,2-dimethyl-1,3-dioxolo[4,5-f][1,10] phenanthroline (1) or 1,10-phenanthroline-5,6-dione (2), acac? acetylacetonate anion. A distorted square-antiprismatic N2O6 environment around central Dy(III) ion is formed by three anions a phenanthroline-type ligand. Both display single-molecule magnet (SMM) behavior at zero applied field. Modification peripheral part ligands provide substantial effects both on relaxation barrier Ueff quantum tunneling magnetization (QTM). Ab initio quantum-chemical calculations are used to analyze electronic properties.