Structures and Magnetic Properties of Bis(μ‐phenoxido), Bis(μ‐phenoxido)‐μ‐carboxylato and Bis(μ‐phenoxido)bis(μ‐carboxylato) Fe III Ni II Compounds – Magnetostructural Correlations

A novel triple aqua-, phenoxo- and carboxylato-bridged dinickel(ii) complex, its magnetic properties, and comparative biomimetic catalytic studies with analogous dinickel(ii) complexes

A unique triply bridged dinickel(ii) complex and two doubly bridged dinickel(ii) complexes are reported, and their magnetic properties and comparative biomimetic catalytic performances are studied.

Solvent-tuned magnetic exchange interactions in Dy2 systems ligated by a μ-phenolato heptadentate Schiff base

A series of binuclear dysprosium compounds, namely, [Dy(api)]₂ (1), [Dy(api)]₂·2CH₂Cl₂ (2), [Dy(Clapi)]₂·2C₄H₈O (3), and [Dy(Clapi)]₂·2C₃H₆O (4) (H₃api = 2-(2-hydroxyphenyl)-1,3-bis[4-(2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazoline; H₃Clapi = 2-(2′-hydroxy-5′-chlorophenyl)-1,3-bis[3′-aza-4′-(2′′-hydroxy-5′′-chlorophenyl)prop-4′-en-1′-yl]-1,3-imidazolidine), have been isolated by the reactions of salen-type ligands H₃api/H₃Clapi with DyCl₃·6H₂O in different solvent systems. Structural analysis reveals that each salen-type ligand provides a heptadentate coordination pocket (N₄O₃) to encapsulate a Dy^III ion and all of the Dy^III centers in 1–4 adopt a distorted square antiprism geometry with D_4d symmetry. Magnetic studies showed that compound 1 did not exhibit single-molecule magnetic (SMMs) behavior. With the introduction of different lattice solvents, compounds 2–4 showed filed-induced slow magnetic relaxation with barriers U_eff of 18.2 K (2), 28.0 K (3) and 16.4 K (4), respectively. Ab initio calculations were employed to interpret the magnetization behavior of 1–4. The combination of experimental and theoretical data reveal the importance of the weak exchange interaction between the Dy^III ions in the observation of slow magnetic relaxation, and a relaxation mechanism has been developed to rationalize the observed difference in the U_eff values. The different lattice solvents influence Dy–O–Dy bond angles and thus alter the torsion of the square antiprism geometry, consequently resulting in distinct magnetic interactions and the magnetic behavior.

Solvent-tuning changes the magnetic exchange interaction and results in different magnetic relaxation dynamics in Dy₂ systems ligated by a μ-phenolato heptadentate Schiff base.

Experimental and theoretical exploration of magnetic exchange interactions and single-molecule magnetic behaviour of bis(η1:η2:μ2-carboxylate)GdIII2/DyIII2 systems

This investigation demonstrates differences in SMM properties and nature of magnetic exchange in closely related DyIII2/GdIII2 compounds.

Syntheses, crystal structures, magnetic properties and ESI-MS studies of a series of trinuclear CuIIMIICuII compounds (M = Cu, Ni, Co, Fe, Mn, Zn)

Six homo/heterotrinuclear Cu^IIM^IICu^II (M = Mn–Zn) compounds derived from salicylaldehyde-trans-1,2-diaminocyclohexane, which is a rarely utilized ligand, are reported.

Magnetic Properties of a Dinuclear Nickel(II) Complex with 2,6-Bis[(2-hydroxyethyl)methylaminomethyl]-4-methylphenolate

Magnetic properties of dinuclear nickel(II) complex [Ni₂(sym-hmp)₂](BPh₄)₂·3.5DMF·0.5(2-PrOH) (1), where (sym-hmp)^- is 2,6-bis[(2-hydroxyethyl)methylaminomethyl]-4-methylphenolate anion and DMF indicates dimethylformamide, were investigated using high-frequency and -field electron paramagnetic resonance (HFEPR). To magnetically characterize the mononuclear nickel(II) species forming the dimer, its two dinuclear zinc(II) analogues, [Zn₂(sym-hmp)₂](BPh₄)₂·3.5DMF·0.5(2-PrOH) (2) and [Zn₂(sym-hmp)₂](BPh₄)₂·2acetone·2H₂O (2'), were prepared. One of them (2') was structurally characterized by X-ray diffractometry and doped with 5% mol nickel(II) ions to prepare a mixed crystal 3. From the HFEPR results on complex 1 obtained at 40 K, the spin Hamiltonian parameters of the first excited spin state (S = 1) of the dimer were accurately determined as |D₁| = 9.99(2) cm^-1, |E₁| = 1.62(1) cm^-1, and g₁ = [2.25(1), 2.19(2), 2.27(2)], and for the second excited spin state (S = 2) at 150 K estimated as |D₂| ≈ 3.5 cm^-1. From these numbers, the single-ion zero-field splitting (ZFS) parameter of the Ni(II) ions forming the dimer was estimated as |D_Ni| ≈ 10-10.5 cm^-1. The HFEPR spectra of 3 yielded directly the single-ion parameters for D_Ni = +10.1 cm^-1, |E_Ni| = 3.1 cm^-1, and g_iso = 2.2. On the basis of the HFEPR results, the previously obtained magnetic data (Sakiyama, H.; Tone, K.; Yamasaki, M.; Mikuriya, M. Inorg. Chim. Acta 2011, 365, 183) were reanalyzed, and the isotropic interaction parameter between the Ni(II) ions was determined as J = -70 cm^-1 (H_ex = -J S_A·S_B). Finally, density functional theory calculations yielded the J value of -90 cm^-1 in a qualitative agreement with the experiment.

Syntheses, crystal structures and steady state and time-resolved fluorescence properties of a PET based macrocycle and its dinuclear ZnII/CdII/HgII complexes

The present report deals with solution spectroscopic (absorption and emission) and colorimetric studies of a Robson type tetraaminodiphenol macrocyclic ligand and its ZnII2, CdII2 and HgII2 compounds.