A Strongly Spin-Frustrated Fe(III) 7 Complex with a Canted Intermediate Spin Ground State of S=7/2 or 9/2

An [FeIII8] molecular oxyhydroxide

An [Fe^III₈] hexagonal bipyramid displays antiferromagnetic exchange between the two capping tetrahedral ions and the six ring octahedral ions resulting in a spin ground state of S = 10.

A triple-triangle cluster derived from a simple tridentate ligand

The heptanuclear ferric cluster, [FeIII7(O)6(HL)5(H2L)(H2O)8](BF4)4 (H2L = 2,6-bis(1,5-diphenyl-1H-pyrazol-3-yl)pyridine), was synthesized by the reaction of the planar tridentate ligand H2L with iron(ii) tetrafluoroborate hexahydrate. The cluster has a corner-shared triple-triangle core structure connected by three μ-O atoms, and it has a spin-frustrated ferrimagnetic spin ground state of S = 19/2.

A disc-like Co7 cluster with a solvent dependent catecholase activity

Herein, we report the first example of a new Co₇ disc-like cluster with a solvent dependent catecholase activity characterized by spectral, X-ray and magnetic studies.

Different magnetic responses observed in Co, Co and Co-based MOFs

Four magnetic MOFs with anisotropic Co(II) ions, {[Co5(H2O)2(μ3-OH)2(atz)2(stp)2]·1.5H2O}n (1), {[Co5(H2O)2(μ3-OH)2(trz)2(stp)2]·1.3H2O}n (2), {[Co5(H2O)6(μ3-OH)2(trz)2(stp)2]·2.5CH3OH}n (3) and {[Co3(H2O)4(Hdatrz)2(stp)2]·3H2O}n (4) (stp(3-) = 2-sulfoterephthalate, trz(-) = 1,2,4-triazolate, atz(-) = 3-amino-1,2,4-triazolate and Hdatrz = 3,5-diamino-1,2,4-triazole) were solvothermally isolated by varying the substituent groups appended on the N-heterocyclic triazole and structurally and magnetically characterized. Structural analyses indicate that the former two complexes are crystallographically isostructural, exhibiting pillared-layer frameworks with mixed triazolyl and carboxylate extended Co + Co layers supported by rigid stp(3-) connectors. Complex 3 is built from butterfly-shaped Co cluster-based layers, which are interconnected with single cobalt(ii) octahedra by ditopic stp(3-) bridges. By contrast, complex 4 consists of linear {Co3(μ-N1,N4-Hdatrz)2} subunits, which are extended by 3-connected stp(3-) linkers into a stable 3D framework. Magnetically, 1 exhibits ferromagnetic ordering below 2.7 K due to the well-organized alignment of the non-compensated resultant moment from octahedra and tetrahedral cobalt(ii) carriers, while 3 is in a non-zero paramagnetic state above 2.0 K resulting from the coexistence of intermetallic ferromagnetic and antiferromagnetic interactions. The magnetic competition between weak inter-subunit antiferromagnetic interactions and the external magnetic field makes 4 behave as a field-induced metamagnet with a critical field of 27.5 kOe. These interesting magnetostructural results suggest that the anisotropy of the moment carrier and the interlayer/intersubunit separations significantly dominate the magnetic responses in extended MOFs, providing an informative platform for the further development of interesting magnetic materials, both of academic and industrial interest.

Magnetism behaviours dominated by the interplay of magnetic anisotropy and exchange coupling in local CoII7 discs

Structure and magnetism of two CoII7 disc-based layers were reported. An asymmetric CoII7 core in the (4,4) layer exhibited single-molecule magnetic behavior. A highly symmetric C_2h CoII7 disc in the (3,6) sheet showed ferromagnetic exchange.