[M(N₃)₂(H₂O)₂]⋅(bpeado): Unusual Antiferromagnetic Heisenberg Chain (M=Mn) and Ferromagnetic Ising Chain (M=Co) with Large Coercivity and Magnetic Relaxation (bpeado=1,2‐Bis(4‐pyridyl)ethane‐N,N′‐dioxide)

Abstract

We present here the structures and magnetism of two isostructural magnetic metal-azido chain compounds of the type [M(N(3))(2)(H(2)O)(2)](bpeado) (1, M = Mn; 2, M = Co; bpeado = 1,2-bis(4-pyridyl)ethane-N,N'-dioxide), prepared by utilizing the long spacer bpeado. The structure is composed of [M(N(3))(2)(H(2)O)(2)](n) metal-azido chains, in which metal ions are bridged by two end-on azido ligands, and the chains are further supported by H-bonding interactions between the coordination water of the chain and the lattice bpeado in a three-dimensional (3D) threefold interpenetrated H-bonded framework. Within the structure, the metal-azido chains are separated quite well. Investigation of the magnetic properties has revealed that the Mn compound 1 is an isotropic Heisenberg chain with unusual antiferromagnetic coupling between the Mn(2+) ions linked by double end-on azide anions. The Co compound 2 shows a strong anisotropic Ising-type ferromagnetic chain within the material. Detailed magnetic studies on both polycrystalline and single-crystal samples of 2 have revealed a large coercivity of up to 37.5 kOe (along the crystallographic b-axis), multi-magnetic transitions, and single-chain-magnet-like magnetic relaxation behavior.

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

“…24). Several SCMs have been reported using end-on azides [39,41,42,[44][45][46]49,52,74,89,94,96,127], and a handful have been reported using end-to-end azides [76,88,97,98]. Hendrickson and co-workers reported a mixed end-on end-to-end azide SCM (Fig.…”

Diversified architectures of one-dimensional zinc(II) and cadmium(II) coordination polymers incorporating bipyridyl ligands: Syntheses, structures, theoretical studies, fluorescent and nonlinear optical properties

“…spacers have given very interesting structural motifs recently, including double helices, double sheets, simple and interpenetrated ladders, intertwined brick-wall frameworks, interpenetrated diamondoid nets and other remarkable species [38][39][40][41].…”

Intermolecular interaction and magnetic coupling mechanism on a mononuclear CoII complex

“…The variable-temperature (2.00-300 K) magnetic susceptibilities are shown in figure 5, where M is the molar magnetic susceptibility per Co II and eff is the magnetic moment per Co II . Figure 5 shows that the M value increases with decreasing temperature, reaching a maximum at 2.00 K. The eff at 300 K is 4.61 B.M., larger than the value expected for an isolated spin-only (3.87 B.M., g av ¼ 2) at room temperature, indicating an important orbital contribution is involved [41]. The eff value decreases very slowly with temperature drop until about 80.0 K, and then eff decreases sharply with temperature drop and reaches 3.58 B.M.…”