A two-dimensional Ni(II) coordination polymer built of 4-(1,2,4-triazol-4-yl)phenylphosphonate: Synthesis, structure and ferromagnetic magnetic property

•A two-dimensional Ni(II) coordination polymer containing isolated 1D Ni(II) chains.•Reversible dehydration and rehydration induced phase transformation.•Ferromagnetic coupling mediated in the chain.•Theoretical calculation reveals the exchange path.

Hydrothermal reaction of NiCl2 and H2ptz ligand leads to the formation of a two-dimensional Ni(II) coordination polymer, named as [Ni(Hptz)(μ2-Cl)]·2H2O (1, H2ptz = 4-(1,2,4-triazol-4-yl)phenylphosphonate acid), which contains 1D Ni(II) chain structure with a Ni⋯Ni distance of 3.704 Å, and shows a (3,6)-connected net with a Schläfli symbol of (3.62)2(34.42.84.95). Magnetic study reveals a ferromagnetic coupling mediated in the chain structure with a fitted J value of 5.0 K. Furthermore, theoretical calculation suggests that the exchange path of Ni–Cl–Ni with spin orbit of dxz–pz–dxz contributes mainly to the ferromagnetic coupling.

Graphical abstractA two-dimensional Ni(II) coordination polymer which contains 1D Ni(II) chain structure has been synthesized. Magnetic study reveals a ferromagnetic coupling, and theoretical calculation suggests that the exchange pathway of Ni–Cl–Ni with spin orbit of dxz–pz–dxz contributes mainly to the ferromagnetic coupling.Figure optionsDownload full-size imageDownload as PowerPoint slide