Ionothermal synthesis, crystal structures and magnetic properties of two nickel(II) coordination polymers based on tetrazole-1-acetic acid

Abstract Ionothermal reaction of NiCl 2 ·6H 2 O and tetrazole-1-acetic acid (1-Htza) in ionic liquid [BMIM]Br (BMIM = 1-butyl-3-methylimidazolium) afforded a new 3D Ni(II) coordination polymer [Ni(1-tza) 2 ] n 1 . When 2,2′-bipy was introduced, another 1D chained polymer, [Ni(1-tza)(2,2′-bipy)(H 2 O) 2 ] n X n ·2nH 2 O ( 2 , X = 0.78Br + 0.22Cl) was acquired. Both compounds have been structurally characterized by single-crystal X-ray diffraction analyses. In the obtained compounds, 1-Htza ligands adopt two different coordination modes: μ 3 - κ N4: κ O1: κ O2 for 1 , and μ 2 - κ N4: κ O1 for 2 . The temperature-dependent magnetic susceptibilities of 1 and 2 have been measured and theoretically fitted by means of a 1-D chain model. A ferromagnetic interaction between Ni(II) ions exists in 1 with J  = 3.24 cm − 1 , while an antiferromagnetic interaction in 2 with J  = − 5.72 cm − 1 .