Syntheses, Structures, Magnetism and Fluorescence Studies of Two 1D Cu(II) Coordination Polymers Based on Bipyridyl Ligands

Abstract

Two one-dimesional (1D) coordination polymers (CPs) [Cu2(μ 2-OAc)4(μ 2-bpt)] n (1) and [Cu(μ t-DMF)(μ t-NO3)2(μ 2-bpmh)] n (2) (DMF = N,N-dimethylformamide) based on copper(II) salts and 3,5-bis(4-pyridyl)-1,2,4-triazole (bpt) and 1,2-bis(pyridin-4-ylmethylene)hydrazine (bpmh) have been synthesized under different conditions, respectively; and characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analyses, powder X-ray diffraction, fluorescence analysis, fourier transforming infrared and ultraviolet–visible spectroscopies. CP 1 shows an infinite 1D zigzag chain with paddle-wheel shaped [Cu2(μ 2-OAc)4] secondary building units (SBUs) and μ 2-bpt V-shaped dipyridyl ligands. The Cu···Cu distance in the [Cu2(μ 2-OAc)4] core is 2.631(18) A, supporting the Cu···Cu interaction. Cu(II) in CP 2 also adopts five-coordinated mode but in trigonal bipyramidal geometry which is completed by three O atoms from nitrates and DMF and also two N atoms from adjacent bpmh to form an infinite 1D linear chain. Furthermore, the magnetism property of CP 1 was investigated. Its results show that CP 1 indicated antiferromagnetic behavior. In addition, CPs 1 and 2 display fluorescence quenching compared with corresponding free ligands at room temperature. CPs 1 and 2 were hydrothermally synthesized and solution interdiffusion procedure, respectively. Both of which show 1D infinite zigzag chain but pack in different patterns. CP 1 shows an infinite 1D zigzag chain with paddle-wheel shaped [Cu2(μ 2-OAc)4] secondary building units (SBUs) and μ 2-bpt V-shaped dipyridyl ligands. Cu(II) in CP 2 also adopts five-coordinated mode but in trigonal bipyramidal geometry which is completed by three O atoms from nitrates and DMF and also two N atoms from adjacent bpmh to form an infinite 1D linear chain. CP 1 shows antiferromagnetic behavior. Both CPs 1 and 2 display fluorescence quenching compared with corresponding free ligands at room temperature.