Magnetic Relaxation Dynamics of a Binuclear Diluted Er(III)/Y(III) Compound Influenced by Lattice Solvent.

It is crucial to investigate the slow relaxation mechanisms of binuclear ErIII -based single-molecule magnets (SMMs) and explore strategies for optimizing their magnetic properties. Herein, a doped compound, [Y1.75 Er0.25 (thd)4 Pc] ⋅ 2C6 H6 (YEr ⋅ 2C6 H6 , Hthd=2,2,6,6-tetramethylheptanedione, H2 Pc=phthalocyanine), was synthesized by doping the paramagnetic erbium(III) compound Er2  ⋅ 2C6 H6 in the diamagnetic yttrium(III) matrix Y2  ⋅ 2C6 H6 . The doping effect was studied using SQUID magnetization measurements. The results suggest that magnetic-site dilution improves the magnetic property from a fast relaxation of the pure ErIII compound to a typical SMM relaxation process of the doped sample. In this binuclear system, the dominant single-ion relaxation is entangled with the neighboring ErIII ion through the intramolecular ErIII ⋅⋅⋅ErIII interaction, which plays an important role in suppressing the quantum tunneling of the magnetization (QTM) process. Furthermore, the influence of lattice solvents on single-ion relaxation was studied. By releasing the benzene molecules, compound YEr ⋅ 2C6 H6 can be successfully transformed to a desolvated sample YEr accompanied by structural alteration and improved SMM performance.