Crystal structure of a Two-dimensional coordination polymer [Ba ₂(phen)₄(tp)₂]n

A novel two-dimensional coordination polymer [Ba₂(phen) ₄(tp)₂]n (phen = 1, 10phenanthroline, tp = terephthalic acid) has been synthesized with tp as bridge ligands and structurally determined by X-ray crystallography. The crystal belongs to the monoclinic system, space group C2/c, with a = 18.877(4), b = 18.489(4), c = 15.658(3) Å, ß = 103.61(3)°, V= 5311.5(19) ų, C₃₂H ₂₀O₄N₄Ba, M_r = 661.86, Z= 8, F(000) = 2624, μ = 1.542 mm^-1, D_c= 1.655 g/cm₃, the final R = 0.0228 and wR = 0.0554 for 6063 observed reflections (I > 2σ(I)). The structural analysis shows that each tp ligand bridges barium atoms to form a two-dimensional infinite layer. There are aromatic π-π stacking interactions between neighboring layers, and aromatic π-π interactions further extend such layers into a three-dimensional supramolecular framework.