Solvent Modification of the Structures and Magnetic Properties of a Series of Dysprosium(III) Single-Molecule Magnets

Abstract

Solvent effects on the structures and magnetic properties of single-molecule magnets (SMMs) have been of great interest for modification of the SMMs using chemical modulation. By systematically varying the reaction solvents (MeOH, ethanol, n-propanol, and n-butanol), we have successfully synthesized a series of DyIII-H4daps complexes (H4daps = N′,N‴-[(1E,1′E)-pyridine-2,6-diylbis(ethan-1-yl-1-ylidene)]bis(2-hydroxybenzohydrazide), including two binuclear compounds, [Dy2(H2daps)2(MeOH)4(H2O)2](CF3SO3)2·0.5MeOH (1 MeOH ) and [Dy2(H2daps)3(EtOH)2]·2EtOH·Et2O (2 EtOH ), and two mononuclear compounds, [Dy(H4daps)2](CF3SO3)3·n-PrOH (3 PrOH ) and [Dy(H4daps)(CF3SO3)3(n-BuOH)]·0.5Et2O (4 BuOH ). Using different solvents, the ligand-to-metal ratios can be adjusted from 1:1 in 1 MeOH and 4 BuOH to 3:2 in 2 EtOH and 2:1 in 3 PrOH . Through the solvent crossover experiments, the role of the solvents and the conditions to form these complexes were carefully studied. The size of the different alcohols, their coordination ability to the DyIII center, and the solubility of the complexes in these alcohols might affect the assembly process and lead to modification of the structures and magnetic properties of these DyIII-H4daps complexes. Magnetic studies revealed that these four complexes all exhibit slow magnetic relaxation under a zero or an applied direct-current field, with an energy barrier of about 100 K for the binuclear compound 1 MeOH . In combination with theoretical calculations, the magnetic–structure relationship of these four compounds has been analyzed. This work demonstrates the crucial role of different solvent molecules in the fine-tuning of the structures and magnetic performances of different lanthanide complexes.

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

“…These features might reveal the occurrence of low-lying energy states or anisotropies for the two complexes. 61–63 In addition, no apparent magnetic hysteresis loops at 2 K were observed for the two title clusters as shown in Fig. S10 (ESI†).…”

LnIII/MnII–LnIII complexes derived from a salicylic azo dye ligand: synthesis, structures, magnetic and fluorescence properties

“…The difference between the two Tb complexes is due to the influence of coordinated DMF/water molecules and/or lattice water molecules. 63–65 The relaxation processes of 4f complexes ( 1 and 2 ) are also different from those of 3d–4f complexes ( 3 and 4 ), which is due to the introduction of 3d ions. 66–68 These results prove again that the magnetic behaviors can be controlled through external conditions.…”

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

“…Indeed, Schiff base ligands behave as O- and N-multidentate ligands that can readily form many types of coordination pockets to coordinate with Dy III ions. Moreover, the O atom bridges with the metal ions, whereas the N atom has a regulating effect on the ligand field strength; thus, the Schiff base ligand is an excellent choice for synthesizing SMMs. , For the same ligand, complex formation with different nuclear numbers in a rationally regulated coordination environment is extremely interesting and important for additional study of the magneto-structural correlations of multinuclear SMMs. − …”