Li-Fang Zhang

Synthesis, crystal structure, and magnetism of a two-dimensional copper(II) complex with single end-to-end and double end-on azide bridges

A new azido-bridged copper(II) complex, [Cu(dmp)(µ 1,1-N3)(µ 1,3-N3)] n (1) (dmp = 3,5-dimethylpyrazole), has been structurally and magnetically characterized. X-ray diffraction analysis indicates that the compound consists of double end-on (EO) azido-bridged dimers which are linked by single end-to-end (EE) azide bridges to form a 2-D layer-like structure. Magnetic investigation demonstrates an overall ferromagnetic interaction in 1 and both azide bridges (EE and EO) transmit ferromagnetic coupling. At low temperature (T < 2.5 K), the compound exhibits some metamagnetic behavior.

Field-Induced Slow Magnetic Relaxation in an Octacoordinated Fe(II) Complex with Pseudo-D2d Symmetry: Magnetic, HF-EPR, and Theoretical Investigations

An octacoordinated Fe(II) complex, [FeII(dpphen)2](BF4)2·1.3H2O (1; dpphen = 2,9-bis(pyrazol-1-yl)-1,10-phenanthroline), with a pseudo-D2d-symmetric metal center has been synthesized. Magnetic, high-frequency/-field electron paramagnetic resonance (HF-EPR), and theoretical investigations reveal that 1 is characterized by uniaxial magnetic anisotropy with a negative axial zero-field splitting (ZFS) (D ≈ -6.0 cm-1) and a very small rhombic ZFS (E ≈ 0.04 cm-1). Under applied dc magnetic fields, complex 1 exhibits slow magnetic relaxation at low temperature. Fitting the relaxation time with the Arrhenius mode combining Orbach and tunneling terms affords a good fit to all the data and yields an effective energy barrier (17.0 cm-1) close to the energy gap between the ground state and the first excited state. The origin of the strong uniaxial magnetic anisotropy for 1 has been clearly understood from theoretical calculations. Our study suggests that high-coordinated compounds featuring a D2d-symmetric metal center are promising candidates for mononuclear single-molecule magnets.

Two Cyanide-Bridged Heterometallic One-Dimensional Chain Complexes Constructed by Hydrogen Bond Interactions: Synthesis, Crystal Structures, and Magnetic Properties

Two trinuclear cyanide-bridged heterometallic Ni(II)– Mn(III) complexes {[Mn(L1)(H2O)]2[Ni(CN)4]} 2H2O (1) and {[Mn(L2)(H2O)]2[Ni(CN)4]} (2) (L1 = N,N-ethylene-bis(3-methoxysalicylideneiminate; L2 = N,N-ethylene-bis(3-ethoxysalicylideneiminate) have been obtained by using [Ni(CN)4]2− and two manganese(III) compounds containing bicompartimental Schiff base ligands as assembling segments. X-ray diffraction reveals that the two cyanide-bridged trinuclear complexes are self-complementary through intermolecular O–H…O hydrogen bond interactions formed by a coordinated aqua ligand from one molecule and the four phenolic oxygen atoms from the neighboring one, giving a supramolecular one-dimensional chain structure. Investigation of the magnetic susceptibilities of these two complexes reveals the overall weak antiferromagnetic interactions between the adjacent Mn(III) ions.