Assembly Studies of Two Planar Dy₄ Single-Molecule Magnets

Abstract

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.

Structure and assembly studies of two planar Dy(iii) single molecule magnets with double relaxations

“…Their χ m T values of 57.87 and 79.34 cm 3 K mol −1 at 300 K are near to the corresponding theoretical values of 56.68 and 85.02 cm 3 K mol −1 based on four and six isolated Dy( iii ) ions ( 6 H 15/2 , S = 5/2, L = 5, J = 15/2, and g = 4/3) for 1 and 2 , respectively. 21,56,57 Upon cooling the sample, a slight decrease was observed for the χ M T values of 1 and 2 before 100 and 69 K, with an subsequent rapid decrease to 37.08 and 35.94 cm 3 K mol −1 at 2 K, respectively. This kind of behavior is believed to be caused by the synergistic effect of thermally reduced Stark energy levels and intermetallic magnetic interactions or dipole–dipole interactions.…”

“…Our group has ever reported the magnetic properties and assembly processes of 4f and 3d–4f clusters with the aim to disclose the assembly mechanisms of 4f and 3d–4f SMMs. 47,57,77–79 In comparison, the two titled Dy( iii ) clusters present much simpler structures with planar tetranuclear and hexanuclear skeletons, but they are zero-field SMMs with rarely reported double relaxations. With a desire to explore the assembly mechanism of 1 and 2 , high-resolution mass spectrometry was used to track the formation reactions of 1 and 2 by collecting and analyzing the mass spectra (Fig.…”

Structures and Single-Molecule Magnet Behavior of Dy3 and Dy4 Clusters Constructed by Different Dysprosium(III) Salts

“…To explore the magneto-structural correlations of tetranuclear Dy III -based SMMs, this class of complexes were summarized (Table S13). − The nuclear centers of tetranuclear Dy III complexes have various shapes such as linear, cymbiform, and parallelogram. (Figure ).…”