Assembly Studies of Two Planar Dy₄ Single-Molecule Magnets

Two tetranuclear Dy(III) complexes formulated as [Dy4(L1)2(L′)4(EtOH)2(CH3CN)2(H2O)2]Cl2 (1) and [Dy4(HL2)2(L′)4(MeOH)6]Cl2·3MeOH·2CH3CN (2) were synthesized from the reactions of DyCl3·6H2O with the corresponding 2-hydroxy-1-naphthaldehyde Schiff bases under hydrothermal conditions (H3L1 = 2-methyl-2-((2′-hydroxynaphthalen-1′-yl)methyleneamino)propanediol, HL′ = 2-hydroxy-1-naphthaldehyde, and H4L2 = 2-(hydroxymethyl)-2-((2′-hydroxynaphthalen-1′-yl)methyleneamino)propanediol). The two Dy(III) complexes possess planar rhombus tetranuclear skeletons with different substitution groups on the Schiff base ligand. The magnetic investigation revealed field-induced single-molecule magnets for the two titled clusters. It suggests that both coordinated solvent molecules and substitution groups have a certain tuning effect on the single-molecule magnet performance. Their assembling processes were further investigated through time-dependent high-resolution electrospray ionization mass spectrometry, giving possible assembling mechanisms for the two titled single-molecule magnets.