A 3D coordination polymer of Tb( iii ) of formula [Tb(bttb) _0.5 (2,5-pzdc) _0.5 ] _n , where two polycarboxylate ligands act as linkers, exhibits a maximum relative sensitivity of 0.76% K ⁻¹ at 295 K.

The heterobimetallic 15-MC-5 metallacrown of formula [CeCu₅(5mpzHA)₅(NO₃)(H₂O)₇]·2NO₃·7H₂O, designated MC-Ce, was synthesized using 5-methyl-2-pyrazinehydroxamic acid (5mpzHA) as a linker, reacting with Ce^III and Cu^II salts under mild conditions. Single-crystal X-ray diffraction analysis reveals a crown-like [Cu₅Ce(5mpzHA)₅] core, characteristic of a 15-MC-5 system, with five Cu^II atoms at the rim of the crown and the Ce^III ion occupying the dome of the crown, with water molecules, oxygen atoms and one nitrate anion filling the nine-coordination sphere around the Ce^III ion, which exhibits a distorted spherical tricapped trigonal prism geometry. The thermogravimetric analysis evidences successive mass losses due to the removal of water molecules and decomposition of the structure after 217 °C, whereas the PXRD analysis of the thermal decomposition residue reveals the presence of copper and copper/cerium oxide particles. These nanocomposite materials were also synthesized using the metallacrown MC-Ce under a hydrothermal method in the presence of multi-walled carbon nanotubes (MWCNTs), affording insights that this metallacrown can act as a source precursor for the synthesis of these mixed cerium/copper oxide nanomaterials. The experimental χMT value in MC-Ce at room temperature is 3.175 cm³ mol⁻¹ K, which is higher than the calculated one for one magnetically isolated Ce^III plus five Cu^II ions, probably due to the antiferromagnetic interactions among Cu^II ions within the metallacrown hoop plus the thermal depopulation of JZ sublevels of Ce^III ground state (5/2), which exhibit a small splitting under the anisotropic ligand field effects. The χMT decreases continuously until it reaches the value of 0.80 cm³ mol⁻¹ K at 10 K, reinforcing the presence of intramolecular antiferromagnetic interactions.

Two homonuclear coordination networks of general formula [{Co(H₂mpba)(dps)}·2DMSO]_n (1) and [{Cu(H₂mpba)(dps)}·2DMSO·H₂O]_n (2) [H₄mpba = 1,3-phenylenebis(oxamic) acid; dps = 4,4′-dipyridyl sulfide] were prepared by the diffusion method at room temperature, characterized, and their magnetic properties investigated. The starting 4,4′-dipyridyl disulfide (dpds) ligand undergoes complete in situ transformation into dps under mild conditions, affording the two-dimensional polymeric arrays. The H₂mpba²⁻ exhibits the bis-bidentate coordination mode, and the dps serves as a bridging ligand between two metal centers, yielding a two-dimensional coordination network with a triangular-like structure, in which the metal ions act as connecting nodes. AC measurements demonstrate that they exhibit slow magnetic relaxation in the absence of an applied DC field (1) and under an applied direct-current (DC) field (2), with a single bottleneck effect. Compound 1 shows a weak but clear out-of-phase signal at zero field, confirming a single-ion magnet (SIM) behavior. At 1 kOe, a bottleneck effect dominates below 7.5 K. At the same time, the Orbach process prevails at 7.5–11.5 K, supported by strong easy-axis anisotropy (D = −103.7(7) cm⁻¹) (D = −106.0 cm⁻¹ and ∣E/D∣ = 0.23 from ab initio CASSCF/NEVPT2 calculations), and significant rhombicity, yielding an effective energy barrier, U_eff = 56(3) K with a pre-exponential factor of relaxation time, τ₀ = 1.2(1) × 10⁻⁸ s. Compound 2 displays field-induced slow relaxation at 1 kOe due to the bottleneck effect.