Multifunctional Dy3+ Complexes with Triphenylmethanolates: Structural Diversity, Luminescence, and Magnetic Relaxation

Abstract

The coordination environment of magneto-luminescent Dy3+-based Single-Molecule Magnets (SMM) is a crucial factor influencing both magnetic and luminescent properties. In this work, we explore how triphenylmethanolate (Ph3CO−), in combination with other ligands, can modulate the structure and, therefore, the magnetic properties of Dy3+-based SMM. Using triphenylmethanolate in combination with THF and pyridine (Py) as co-ligands, we synthesized a series of mononuclear cis-[Dy(OCPh3)2(THF)4][BPh4]·(2,6-Me2C5H3N) (1), trans-Dy(OCPh3)3(THF)2 (2), fac-Dy(OCPh3)3(py)3 (3) and dinuclear [(Ph3CO)Dy(THF){(μ2–Cl)2Li(THF)2}μ2–Cl]2 (4) complexes where the Dy3⁺ ion presents five- or six-coordinate geometries. Dinuclear compound 4 exhibits a genuine SMM behavior with a relatively high energy barrier of 421 cm−1, while mononuclear complexes 1–3 are field-induced SMM. These complexes also present Dy3+-characteristic luminescence, highlighting their multifunctional character.