Thermostability and photoluminescence of Dy(iii) single-molecule magnets under a magnetic field† †Electronic supplementary information (ESI) available: Additional magnetic data, additional figures and computational details. CCDC 1446709–1446713. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc01157h

A series of promising multifunctional lanthanide single-molecule magnets (SMMs). Lanthanide luminescence under a pulsed magnetic field for SMMs is examined for the first time.
A series of compounds [ADyL4]·[solvent] composed of a dysprosium(iii) ion coordinated by four chelated naphthyridine-like ligands (L = 4-hydroxy-8-methyl-1,5-naphthyridine-3-carbonitrile) and an alkali metal ion (A = Na, K, Rb, Cs) were synthesized and characterized. They behave as single-molecule magnets under a zero dc field with an effective energy barrier of around 95 cm–1. Meanwhile, the main part, [ADyL4], of these SMMs is thermostable and sublimable. The geometric structures of three sublimed compounds are identical to the original ones without solvents, which is confirmed by X-ray diffraction using single crystal and powder samples. The static and dynamic magnetic properties remain unchanged before and after sublimation. Luminescence measurements at 5–77 K were performed to verify the energy gap between low-lying states and to understand the pathway of the thermal relaxation process of magnetization, as well as to inspect the tiny variation in magnetic sublevels for the ground term of Dy(iii). The photoluminescence spectra under a magnetic field (0–36 T) for the Dy-SMMs are investigated for the first time. The energy splitting of the two lowest sublevels of the ground term 6H15/2 of Dy(iii) are analyzed using the Zeeman formula.