Cesium Cyano-Bridged CoII–MV (M = Mo and W) Layered Frameworks Exhibiting High Thermal Durability and Metamagnetism

Two-dimensional cesium bimetal cyano-bridged assemblies CsI4CoII[MoV(CN)8]­Cl3 (CsCoMo) and CsI4CoII[WV(CN)8]­Cl3 (CsCoW) were synthesized. The negatively charged and solvent-free {CoII[MV(CN)8]­Cl3}4– (M = Mo, W) coordination layers are separated by Cs+ ions. Themogravimetric measurements show that these compounds reveal high thermal durability up to 523 K (250 °C), which is due to the absence of solvent molecules in their crystal structures. The magnetic measurements show that CsCoMo and CsCoW are metamagnets showing the field-induced transition from an antiferromagnetic phase with Néel temperature of 25 K to a ferromagnetic phase, which is observed at high critical magnetic field of 24 kOe at 1.8 K. These originate from antiferromagnetic interactions between ferromagnetically coupled cyano-bridged CoII–MV layers, and the contribution from single-ion anisotropy of CoII.