A Single-Chain Magnet Based on {CoII4} Complexes and Azido/Picolinate Ligands

Magnetic relaxation in a Co(ii) chain complex: synthesis, structure, and DFT computational coupling constant

We report a homospin non-solvated Co^II chain compound constructed by two similar tridentate ligands and chloride ions, which displays slow magnetic relaxation below 5 K.

Nonenzymatic Glucose Sensing and Magnetic Property Based On the Composite Formed by Encapsulating Ag Nanoparticles in Cluster-Based Co-MOF

Utilizing the oxygen-bridged 5,5'-oxidiisophthalic acid (H₄L) linker, one Co(II)-based 3D porous MOF {[Co₅(L)₂(OH)₂(OH₂)₂(H₂O)₄]·2DMF·H₂O}_n (1) with pentanuclear [Co₅(μ₃-OH)₂(μ₂-OH₂)₂]⁸⁺ cluster was prepared. The glassy carbon electrode was modified by 1, and the obtained electrode revealed electrocatalytic performance for glucose oxidation. The porous MOF matrix is beneficial for dispersing Ag nanoparticles evenly in the interior cages or channels, so Ag@1 composite composed of both Ag nanoparticles and MOF was further prepared through deposition-reduction method to enhance electrocatalytic activity. The result demonstrates that the glucose oxidation by Ag@1 was greatly increased with low detection limit (1.32 μM) and good selectivity and sensitivity (0.135 μA μM^-1), which promote the application of MOF-template porous composites as advanced electrochemical sensor materials. Furthermore, 1 shows an interesting magnetic spin-glass slow dynamics for the existing of peculiar pentanuclear Co(II) clusters.

Slow magnetic relaxation in a μ1,1'-azido cobalt(ii) methylquinoline chain complex

A [Co(N3)2(mqu)] complex with a 1D chain architecture (mqu - 4-methylquinoline) displays the paramagnetic behaviour with a slight exchange interaction of antiferromagnetic nature among Co(ii) centres. It shows slow magnetic relaxation with three distinct modes. The relaxation time strongly depends upon the applied external field. The slowest relaxation time refers to the low-frequency mode τLF = 1.6(2) s at BDC = 0.8 T and T = 1.9 K.

Ferromagnetically coupled dinuclear MII complexes based on a boratriazine ligand framework

A boratriazine ligand, which incorporates attractive features from both bodipy and terpy, has been used to synthesize [Fe2II(μ1,1-N3)2(Py2F2BTA)2(N3)2] (1) and [Co2II(μ1,1-N3)2(Py2F2BTA)2(N3)2] (2). Both 1 and 2 feature a double end-on azido bridging motif, which promotes ferromagnetic interactions between the metal centres. Indeed, 1 represents the first report of a dinuclear FeII complex with this bridging mode exhibiting J = 5.7(9) cm-1 and D = -6.0(4) cm-1, while the isostructural Co analogue shows J = 7.1(9) cm-1 and D = 17.3(9) cm-1.

Two Isostructural Metal-Organic Frameworks Directed by the Different Center Metal Ions, Exhibiting the Ferrimagnetic Behavior and Slow Magnetic Relaxation

Two 3D isostructural metal-organic frameworks with 1D ferrimagnetic chains, formulated as [M3(L)(μ3-OH)2(H2O)4] [H4L = (1,1':4',1″-terphenyl)-2',3,3″,5'-tetracarboxylic acid, where M = Mn for 1 and Co for 2], have been successfully synthesized by employing different center metal ions and a multicarboxylate ligand under identical reaction conditions in this work. The single-crystal X-ray diffraction data of 1 and 2 reveal that the complexes are two 3D isostructural frameworks based on 1D [M3(OH)2]n chains composed of triangular subunits as rod-shaped secondary building units, which are classified as binodal 4,6-connected fry nets with the point symbol (5(10)·6(3)·7(8))(5(4)·6(2)). The magnetic properties revealed that complexes 1 and 2 exhibit ferrimagnetic behavior. Also, the alternating-current susceptibility of 2 displays slow magnetic relaxation, showing interesting magnetic behavior of a single-chain magnet with an effective energy barrier of 32 K.

Synthesis, magnetism and spectral studies of six defective dicubane tetranuclear {M4O6} (M = NiII, CoII, ZnII) and three trinuclear CdII complexes with polydentate Schiff base ligands

Six defective dicubane face-shared and three trinuclear complexes are synthesized. The magnetic behaviors of Ni^II/Co^II complexes and fluorescence properties of Zn^II and Cd^II are studied.