Controlled Synthesis of Heterotrimetallic Single‐Chain Magnets from Anisotropic High‐Spin 3 d–4 f Nodes and Paramagnetic Spacers

Abstract

By using the node-and-spacer approach in suitable solvents, four new heterotrimetallic 1D chain-like compounds (that is, containing 3d-3d'-4f metal ions), {[Ni(L)Ln(NO(3))(2)(H(2)O)Fe(Tp*)(CN)(3)]⋅2 CH(3)CN⋅CH(3)OH}(n) (H(2)L = N,N'-bis(3-methoxysalicylidene)-1,3-diaminopropane, Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate; Ln = Gd (1), Dy (2), Tb (3), Nd (4)), have been synthesized and structurally characterized. All of these compounds are made up of a neutral cyanide- and phenolate-bridged heterotrimetallic chain, with a {-Fe-C≡N-Ni(-O-Ln)-N≡C-}(n) repeat unit. Within these chains, each [(Tp*)Fe(CN)(3)](-) entity binds to the Ni(II) ion of the [Ni(L)Ln(NO(3))(2)(H(2)O)](+) motif through two of its three cyanide groups in a cis mode, whereas each [Ni(L)Ln(NO(3))(2)(H(2)O)](+) unit is linked to two [(Tp*)Fe(CN)(3)](-) ions through the Ni(II) ion in a trans mode. In the [Ni(L)Ln(NO(3))(2)(H(2)O)](+) unit, the Ni(II) and Ln(III) ions are bridged to one other through two phenolic oxygen atoms of the ligand (L). Compounds 1-4 are rare examples of 1D cyanide- and phenolate-bridged 3d-3d'-4f helical chain compounds. As expected, strong ferromagnetic interactions are observed between neighboring Fe(III) and Ni(II) ions through a cyanide bridge and between neighboring Ni(II) and Ln(III) (except for Nd(III) ) ions through two phenolate bridges. Further magnetic studies show that all of these compounds exhibit single-chain magnetic behavior. Compound 2 exhibits the highest effective energy barrier (58.2 K) for the reversal of magnetization in 3d/4d/5d-4f heterotrimetallic single-chain magnets.

A toolbox of building blocks, linkers and crystallisation methods used to generate single-chain magnets

“…37, as well as Figs. 22 and 38) [21,69,124,137,138]. Amongst them is a particularly interesting cyanide-bridged [Co II Fe III ] chiral SCM that displays both magnetic and electric bistability, reported by the group of Oshio (Fig.…”

[Dy(acac)3(dppn)]·C2H5OH: construction of a single-ion magnet based on the square-antiprism dysprosium(iii) ion

“…The result indicates that a single relaxation time is mainly involved in the present relaxation process. 74 The α value is in the range of previously reported SMMs and SCMs, [40][41][42] which excludes the possibility of spin-glass. In addition, the observed peaks of the out-of-phase signals correspond to the coincidence of the applied ac field oscillation frequency with the relaxation rate.…”

Evolvement of molecular nanomagnets in China

“…Tao, Gao and co-workers [73,74] [76]. Studying the magnetic properties of these four isostructural SCMs with similar magnetic interaction and different magnetic anisotropy helps us to understand the exact effect of magnetic anisotropy on the overall magnetic relaxation process.…”