Synthesis, crystal structure, and magnetic properties of a new cobalt(II) polymer based on 4-bromoisophthalic acid and 1,2-bi(4-pyridyl)ethane

摘要

A new cobalt(II) coordination polymer, [Co _2(bpa) _2(Brip) _2] _n (H _2Brip = 4-bromoisophthalic acid, bpa = 1,2-bi(4-pyridyl)ethane), has been synthesized through hydrothermal reaction. It was characterized by elemental analysis, IR spectra, thermogravimetric analysis, magnetic properties, and X-ray single-crystal diffraction. It crystallizes in the monoclinic space group P _(21)/c with a = 10.2166(16), b = 13.647(2), c = 13.593(2) ?, β = 105.244(2)~°, V = 1828.5(5) ? ~3, C _(40)H _(30)Br _2Co _2N _4O _8, M _r = 972.36, Z = 2, D _c = 1.766 g/cm ~3, μ((MoKα) = 3.154 mm ~1, F(000) = 972, the R = 0.0479, and wR = 0.1251 for 3405 observed reflections with I > 2σ(I). The adjacent Co ions are bridged by Brip to form a 1D chain. The 1D chains are further connected by bpa to generate a 2D network. Variable-temperature magnetic susceptibility measurements indicate the occurrence of weak ferromagnetic properties between adjacent Co ions.