Syntheses, crystal structures and magnetic properties of coordination polymers Ni(NO2)2 and Ni(4,4′-bipy)(NO2)2

Two new coordination polymer frameworks Ni(NO2)2 (1) and Ni(4,4′-bipy)(NO2)2 (2) (4,4′-bipy = 4,4′-bipyridine) were synthesized by solvothermal reaction in formamide, and were characterized by elemental analysis, IR spectroscopy, single crystal X-ray diffraction, and magnetic measurement. In compound 1, each Ni2+ ion is linked with four neighboring Ni2+ ions through μ1,3-nitrito bridges forming 2D layered structure. In compound 2, each Ni2+ ion is bridged with six neighboring Ni2+ ions through four μ1,3-nitrito groups and two 4,4′-bipy ligands forming 3D structure. Magnetic measurements show weak ferromagnetism within framework of the two compounds with TN = 19 K (1) and 21 K (2).

Graphical abstractWe present the use of solvothermal reaction in formamide to synthesize two new frameworks of Ni(NO2)2 and Ni(4,4′-bipy)(NO2)2 containing μ1,3-nitrito bridges. They are the first examples of synthesis of polymeric complexes using solvent as a reducing agent in solvothermal condition. Magnetic measurements show weak ferromagnetism within framework of the two compounds.Figure optionsDownload full-size imageDownload as PowerPoint slide