A formate bridged Ni(II) sheet and its 3D analogue in presence of a linear organic linker: Synthesis, crystal structure and magnetic properties

Reaction of formamide with Ni(NO3)2·6H2O under hydrothermal condition in a mixture of MeOH/H2O forms a two-dimensional formate bridged sheet Ni(HCOO)2(MeOH)2 (1). X-ray structure analysis reveals the conversion of formamide to formate which acts as a bridging ligand in complex 1 where the axial sites of Ni(II) are occupied by methanol used as a solvent. An analogous reaction in presence of 4,4′-bipyridyl (4,4′-bipy) yielded a three-dimensional structure Ni(HCOO)2(4,4′-bpy) (2). DC magnetic measurements as a function of temperature and field established the presence of spontaneous magnetization with Tc (Curie temperature) = 17 and 20.8 K in 1 and 2, respectively, which can be attributed due to spin-canting. DFT calculations were performed to corroborate the magnetic results of 1 and 2.

A formate bridged Ni(II) sheet was prepared by hydrothermal treatment of Ni(NO3)2·6H2O with formamide. A 3D analogue was also synthesized using a pillar linear 4,4′-bipyridyl linker in combination with formamide. Variable temperature magnetic studies indicated spin-canted magnetic behavior in both the cases.Figure optionsDownload as PowerPoint slide