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A β-diketonate mononuclear dysprosium compound, [Dy(TFNB)3(bpy)] (1) (TFNB = 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione, bpy = 2,2′-bipyridine), has been prepared and structurally and magnetically characterized. X-ray crystallographic analysis reveals that 1 contains two crystallographically equivalent Dy(III) ions of which the eight-coordinate geometries uniformly behave as distorted square antiprismatic configurations (D4d). Magnetic investigations demonstrate that 1 displays dual relaxation processes of SMMs behavior with the effective barrier (ΔE/kB) of 23.44 K under 1200 Oe DC field, corresponding to the coexistence of two metal centers in the structure of the compound. The comparative studies of some Dy(III)-based SIMs with TFNB ligand have been conducted as well. Ab initio studies demonstrate that the Kramers doublet ground state is predominantly axial with the gz tensors of two Dy(III) fragments matching the Ising-limit factor (20) anticipated for the pure MJ = ±15/2 state. [ABSTRACT FROM AUTHOR]

We have investigated the dynamic behaviour of the magnetization of a hydrogen-bonding linked Co(II) 1D supramolecular coordination polymer. In the structure, two different mononuclear Co(II) species are linked by O–H···N hydrogen bonding through coordinated H2O and. Field-induced slow magnetic relaxation effect is observed and the anisotropy energy barrier is 33 K.Ab initiocalculations reveal that Co(II) ion in [Co(bpm)2(N3)2] species is uniaxial anisotropic with a negative axial zero-field splitting parameter ofD = − 82.4 cm− 1. The Co(II) ion in [Co(bpm)2(H2O)2]2+species, however, is easy-plane anisotropic with a positiveDand negativeEvalue (D = 46.3 cm− 1,E = − 7.8 cm− 1). This is an interesting complex in which slow magnetic relaxation stems from the combination contribution of uniaxial anisotropy and easy plane anisotropy. [ABSTRACT FROM PUBLISHER]

A new 1-D MnIIchain, [Mn(μ1,3-N3)(phenCl)2]n(ClO4)n(phenCl = 2-chloro-1,10-phenanthroline), was synthesized with singleμ1,3-azido as bridge and 2-chloro-1,10-phenanthroline as coligand, and its crystal structure determined by X-ray crystallography. In the complex, MnIIis located in a distorted octahedral geometry, and azide is an end-end bridge, linking two MnIIions with separation of 5.7356(10) Å, forming a 1-D chain. In the crystal, there are two kinds of π-π stacking between adjacent chains. The fitting of the variable-temperature (2.00–320 K) magnetic susceptibilities gave an anti-ferromagnetic interaction ofJ = –5.99 cm–1(), among the stronger magnetic interaction in MnIIcomplexes with azido as single end-end bridge. Reported experimental results do not confirm clearly the magneto-structural correlations revealed by theoretical calculations. [ABSTRACT FROM AUTHOR]

A new mononuclear complex, [Ni(dpphen)(NCS)2] [dpphen = 2,9-di(1H-pyrazol-1-yl)-1,10-phenanthroline], has been prepared and its crystal structure is determined by X-ray crystallography. In the NiII complex, NiII is a distorted octahedral geometry. The crystal structure analysis shows that there exist π−stacking interactions and an intermolecular interaction among adjacent complexes. The fitting to the variable-temperature magnetic susceptibility data gave the magnetic coupling constant J = −1.37 cm−1 (Ĥ = -JŜ1 ⋅ Ŝ2). Theoretical calculations reveal that the π-stacking magnetic coupling pathway resulted in an antiferromagnetic interaction with 2 J = −0.22 cm−1 (Ĥ = -2JŜ1 ⋅ Ŝ2), whereas the magnetic coupling pathway of the intermolecular interaction led to a ferromagnetic interaction with 2 J = 0.10 cm−1 (Ĥ = -JŜ1 ⋅ Ŝ2). The calculations also display that there occur both spin delocalization and spin polarization in the π-stacking magnetic coupling system and the magnetic coupling system of the intermolecular interaction. [ABSTRACT FROM AUTHOR]