Four model complexes of dysprosium, Dy(N2O2C7H11)3 (Dy2), Dy(NH3)3(H2O)3(OH)3 (Dy3), and a free Dy3+ ion (Dy4) were built by successive capping of the peripheral substitutions of a butterfly-shaped dysprosium complex of a schifbase ligand, Dy(N4O5C14H11)3 (Dy1). The structural modifications were carried out in order to investigate the effect of the chemical surroundings like chelation and aromaticity on the observation of single-molecule magnet (SMM) behaviour in a lanthanide-based complex (Dy1). Experimental techniques were combined with theoretical tools to investigate the dynamics of magnetic properties of the Dy1 and compared with the theoretical results for Dy2, Dy3 and Dy4 to gain insight into the contribution of covalency, crystal field effect and the role of chelation and aromaticity in stabilizing the excited magnetic levels of a single-molecule magnet. 1 showed frequency-dependent slow magnetic relaxation characteristics of a single-molecule magnet with and without applied dc field and a blocking temperature of about 8 K. The obtained results showed that despite f-electrons having weak interactions with ligand field, it is possible to tune the magnetic properties of lanthanide-based complexes using ring currents, chelation, control of covalency and peripheral ligand substituents to induce single-molecule magnet behaviour.

Single-molecule magnet behaviour of a butterfly-shaped mono-nuclear dysprosium complex

ACS Spring 2022

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