Hydrothermal synthesis, crystal structure and magnetic properties of a novel cobalt complex based on biphenyl-3,3′,4,4′-tetracarboxylate

A novel cobalt complex, [Co₂(bptc)(bix)_1.5](l, H ₄bptc = 3,3′,4,4′-biphenyltetracarboxylic acid, bix = l,4-bis(imidazol-l-ylmethyl)benzene), has been hydrothermally prepared and characterized by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The crystal is of triclinic system, space group Pī with a = 10.770(7), b = 12.245(8), c = 13.514(9) Å, a = 102.829(8), β = 107.734(8), y = 98.833(9)°, C₃₇H₂₇N₆O ₈Co₂, M_r = 801.51, V= 1607.5(18) ų, D_c = 1.656 g/cm³, F(000) = 818, = 1.100 mm^-1, Z= 2, the final R = 0.0694 and wR = 0.1543 for 3034 observed reflections (I > 2σ(I)). In the title complex, the two Co(II) ions are in different coordination environments with distorted octahedral and trigonal bipyramidal geometries, respectively. The Co atoms are linked together through hexadentate bptc ligands, giving rise to 2D layers which are bridged by the bix ligands into a 3-D supramolecular network. Magnetic susceptibilities of 1 reveal weak antiferromagnetic exchange interactions between the adjacent Co(II) ions. cobalt(II) complex, crystal structure, biphenyl-3,3′,4, 4′-tetracarboxylate.