Synthesis, Crystal Structure, and Magnetic Properties of a New Cobalt(II) Polymer Based on 4-Bromoisophthalic acid and 1,2-bi(4-pyridyl)ethane

Abstract

A new cobalt(II) coordination polymer, [Co₂(bpa)₂(Brip)₂]_n (H₂Brip = 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 P2₁/c with a = 10.2166(16), b = 13.647(2), c = 13.593(2) Å, β = 105.244(2)°, V = 1828.5(5) ų, C₄₀H₃₀Br₂Co₂N₄O₈, M_r = 972.36, Z = 2, D_c = 1.766 g/cm³, 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.

Keywords:

• cobalt(II) complex
• 4-bromoisophthalic acid
• magnetic properties
• 1
• 2-bi(4-pyridyl)ethane