Synthesis, Topological Analysis and Properties of a Coordination Polymer with Butane-1,2,3,4-tetracarboxylato-bridged (Phenanthroline)cobalt(II) Units

A hydrothermal reaction of Co(Ac)2 · 4H2O, butane-1,2,3,4-tetracarboxylic acid (H4BTC), 1,10-phenanthroline (phen) and NaOH carried out at 160 ◦C yielded a new complex [Co2(H2O)2(phen)2(BTC)]. The complex has been characterized by single-crystal X-ray diffraction, IR spectroscopy, TG-DTA analyses, elemental analyses, powder X-ray diffraction, and magnetic measurements. The Co ions are linked by BTC4− anions into a chain, and hydrogen bonding and π-π stacking interactions result in the formation of a 3D (3,4,6)-connected supramolecular architecture with the Schläfli symbol (4.6.8)2(4.6.8)(6)2. The temperature dependence of the magnetic susceptibility of the compound follows a Curie-Weiss law χm = C/(T −Θ) with C = 4.18(4) cm3 mol−1 K and Θ = −1.43(5) K, and the magnetic behavior can be interpreted by means of a 1D chain Fisher model, where the magnetic superexchange is transmitted via π · · ·π stacking interactions between adjacent phen ligands, and the best fit results in J = −0.05 cm−1, and zJ′ = 0.21 cm−1.