Two new ferromagnetic organic–inorganic hybrid materials {CoII3(H2O)6(pyz)3[WV(CN)8]2}·3.5H2O (1) and {CoII3(H2O)4(4,4′-bpy)3[WV(CN)8]2}·1.5(4,4′-bpy)·6H2O (2) have been synthesised and characterised. The structure of the compounds have been investigated combining EXAFS (extended X-ray absorption fine structure), ES-MS (electrospray mass spectrometry), IR (infrared spectroscopy), UV-VIS electronic spectroscopy and TGA (thermogravimetric analysis) coupled with QMS (quadrupole mass spectrometer) experiments. The studies reveal that both compounds consist of CoII–NC–WV and CoII–L–CoII linkages (L = pyrazine (1) or 4,4′-bipyridine (2)). Both networks are created by cyano-bridged CoII3WV2 chains joined by organic linkers into a 2D architecture. A difference of cobalt coordination numbers in both compounds derived from EXAFS study is consistent with the ES-MS conclusion. The ac magnetic characterisation exhibits the transition to the ferromagnetic phase at TC = 26 K (1) and to the spin glass-like phase at TG = 16 K (2). The frequency dependent χ′(T) and χ″(T) signals indicate the presence of some disorder in spin alignment below ordering temperatures. Both networks are also characterised a by magnetic hysteresis loop of coercive field Hc = 750 Oe (1) and 1200 Oe (2) at T = 4.2 K.
You have access to this article
Please wait while we load your content...
Something went wrong. Try again?