Synthesis, structures and magnetism of heterodinuclear Ni–Ln complexes: field-induced single-molecule magnet behavior in the dysprosium analogue

Abstract

By using the azide anion, hexafluoroacetylacetonato anion (hfac) and compartmental Schiff-base ligand H 2 valpn (H 2 valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol), three isomorphous Ni-Ln heterodinuclear complexes [Ni(valpn)Gd(hfac) 2 N 3 (H 2 O) 2 ]·H 2 O (1), [Ni(valpn)Tb(hfac) 2 N 3 (H 2 O) 2 ]·H 2 O (2) and [Ni(valpn)Dy(hfac) 2 N 3 (H 2 O) 2 ]·H 2 O (3) were synthesized. Structural analyses reveal that the Ni(II) and Ln(III) ions are doubly bridged by two phenoxo oxygen atoms of the valpn ligand. Magnetic susceptibility measurements show ferromagnetic couplings are operative between the Ni(II) andLn(III) ions in 1−3. Ac susceptibility measurements under a dc-applied field of 1000Oe disclose that the Dy derivative exhibits the field-induced single-molecule magnet behavior with effective energy barrier of 16.9 K for reversal of the magnetization.

Synthesis, crystal structure and magnetic properties of octanuclear Ni4Ln4 complexes constructed using a Schiff base ligand and di-2-pyridyl ketone

“…Among the 3d metal ions, Ni II might be one of the better candidates for constructing SMMs because it often possesses a large single-ion zero-field splitting. Up to now, many Ni–Dy heterometallic complexes with different nuclearities like NiDy, 26 Ni 2 Dy, 27 Ni 2 Dy 2 , 28–30 Ni 3 Dy, 31 Ni 4 Dy 2 , 32 Ni 4 Dy 4 , 33 and Ni 8 Dy 4 , 34 and other high-nuclearity Ni–Dy 35 have been reported. Surprisingly, the highest U eff value for these reported Ni–Dy complexes is about 100 K, 29 which is much lower than the values of other 3d-Dy SMMs, such as Fe-Dy, 36 Co III -Dy SMMs, 37 Cu-Dy SMMs 38 and Zn-Dy SMMs.…”

The Crystal Structure and Physicochemical Properties of New Complexes Containing a CuII-LnIII-CuII Core

“…In the reported 3d-Ln III complexes there are examples of hetero-di- [24][25][26][27], tri- [28][29][30], tetra- [27,31,32], and octanuclear [33] compounds (Figure 3). The 3d and 4f metal centers are linked by two phenoxo oxygen atoms of the Schiff base ligands.…”

“…Lanthanide ions, especially Tb III , Dy III , Ho III , and Er III , are widely used in the synthesis of 3d-4f SMMs due to their large ions are arranged linearly and are alternately connected to each other by a bridging element, which may be an acetate ion, for example [19,20]. In the reported 3d-Ln III complexes there are examples of hetero-di- [24][25][26][27], tri- [28][29][30], tetra- [27,31,32], and octanuclear [33] compounds (Figure 3). The 3d and 4f metal centers are linked by two phenoxo oxygen atoms of the Schiff base ligands.…”

“…According to the literature [34][35][36][37][38], significant efforts have been made in recent years to construct 3d-4f compounds to obtain novel single-molecule magnets (SMMs). Lanthanide ions, especially Tb III , Dy III , Ho III , and Er III , are widely used in the synthesis of 3d-4f SMMs due to their large In the reported 3d-Ln III complexes there are examples of hetero-di- [24][25][26][27], tri- [28][29][30], tetra- [27,31,32], and octanuclear [33] compounds (Figure 3). The 3d and 4f metal centers are linked by two phenoxo oxygen atoms of the Schiff base ligands.…”

Unusually Distorted Pseudo-Octahedral Coordination Environment Around CoII from Thioether Schiff Base Ligands in Dinuclear [CoLn] (Ln = La, Gd, Tb, Dy, Ho) Complexes: Synthesis, Structure, and Understanding of Magnetic Behavior

“…To date, a significant amount of study has been undertaken on the synthesis and evaluation of magnetic properties of dinuclear 3d–4f complexes based on Cu II , − Ni II , − Mn II , − and Fe III − ions showing large ground spin states and strong anisotropy. In comparison to these reported works, the corresponding literature containing Co II ions is scarce. , In a regular octahedral crystal field, the Co II ion (3d 7 ) has a 4 T 1g ( 4 F) ground state.…”