Heterometallic Cu^II–Dy^III Clusters of Different Nuclearities with Slow Magnetic Relaxation

Abstract

The synthesis, structures, and magnetic properties of two heterometallic Cu(II)-Dy(III) clusters are reported. The first structural motif displays a pentanuclear Cu(II)4Dy(III) core, while the second one reveals a nonanuclear Cu(II)6Dy(III)3 core. We employed o-vanillin-based Schiff base ligands combining o-vanillin with 3-amino-1-propanol, H2vap, (2-[(3-hydroxy-propylimino)-methyl]-6-methoxy-phenol), and 2-aminoethanol, H2vae, (2-[(3-hydroxy-ethylimino)-methyl]-6-methoxy-phenol). The differing nuclearities of the two clusters stem from the choice of imino alcohol arm in the Schiff bases, H2vap and H2vae. This work is aimed at broadening the diversity of Cu(II)-Dy(III) clusters and to perceive the consequence of changing the length of the alcohol arm on the nuclearity of the cluster, providing valuable insight into promising future synthetic directions. The underlying topological entity of the pentanuclear Cu4Dy cluster is reported for the first time. The investigation of magnetic behaviors of 1 and 2 below 2 K reveals slow magnetic relaxation with a significant influence coming from the variation of the alcohol arm affecting the nature of magnetic interactions.

Metal–Helix Frameworks Formed by μ3‐NO3− with Different Orientations and Connected to a Heterometallic CuII10DyIII2 Folded Cluster

“…The room temperature χ m T value of 32.02 cm 3 K mol −1 is close to that of 32.09 cm 3 K mol −1 as expected for two uncoupled Dy III (28.34 cm 3 K mol −1 , 6 H 15/2 , S= 5/2, L= 5, J= 15/2, g= 4/3) plus 10 Cu II ions ( S= 1/2, g= 2, C =0.375 cm 3 K mol −1 ) . Upon cooling, χ m T decreases slowly to 8 K and drops sharply to reach 17.15 cm 3 K mol −1 at 2 K. This magnetic behavior may be ascribed to the thermal depopulation of Dy III ‐excited Stark sublevels and/or the effect of the exchange interactions among the metal ions (Cu⋅⋅⋅Cu, and Cu⋅⋅⋅Dy) combined with the crystal‐field effect . The M vs. H / T −1 plots of complex at different temperatures are not superposed (Figure S6b, Supporting Information).…”

“…[19] Upon cooling, c m T decreases slowly to 8K and drops sharply to reach 17.15 cm 3 Kmol À1 at 2K.T his magnetic behavior may be ascribed to thet hermal depopulation of Dy III -excited Stark sublevels and/or the effect of the exchange interactions among the metal ions (Cu···Cu, and Cu···Dy) combined with the crystalfield effect. [20] The M vs. H/T À1 plots of complex at different temperatures are not superposed ( Figure S6b, Supporting Information). Slow saturation behavior is found, indicating the relativelys trong magnetic anisotropy,a nd the important crystal-field effect at the Dy III ion that eliminates the 16-fold degen- Figure 2.…”

Syntheses, Structures, and Magnetic Properties of a Series of Heterotri-, Tetra- and Pentanuclear LnIII–CoII Compounds

“…The two symmetry related bipy ligands are located on the two ends as the terminal ligands. The pentanuclear compounds reported in the literature are mostly concentrated in the 3d metal region [23,24,25,26], and the pentanuclear compounds of 3 d– 4 f heterometallic metals are relatively few [27,28,29]. In the reported 3 d– 4 f pentanuclear compounds, the arrangement shapes of pentanuclear metals can be roughly divided into the following types: (a) Trigonal-bipyramidal type [30], (b) Goblet-like [31], (c) Butterfly-shaped [32], (d) Open-book type [33], (e) T-shaped [34] and (f) Sandwich-type [35].…”

Stepwise Investigation of the Influences of Steric Groups versus Counterions To Target Cu/Dy Complexes

“…6,7 However, amongst these, Cu II -Ln III systems have received relatively little attention in terms of their SMM properties up to now. [12][13][14][15][16][17][18][19][20] Nevertheless, it is advantageous for complexes to combine highly anisotropic 4f ions such as Dy III with the quantum spin Cu II d 9 ion. In the case of Cu II -Dy III dimers, which are incorporated into the pockets available in Schiff base ligands incorporating o-vanillin, the coupling between these metal centers is often observed to be ferromagnetic.…”