The new compounds 2,2′-bipyridine-3,3′,6,6′-tetracarboxylic acid (bptcH4) (1) and iron(II) [Fe2(bptcH2)2(H2O)4]·4.74H2O (2) and [Co2(bptcH2)2(H2O)4]·4.5H2O (3) have been prepared and characterized using 1H NMR, IR and UV-Vis spectroscopic methods. X-Ray structures of these compounds have been determined. Acid 1 crystallizes in the space group Aba2 and complexes 2 and 3 in P21/c. The metal atoms are coordinated with N and O atoms of 6,6′ carboxylate groups of the bridging ligands and two aqua ligands. The crystals are stabilized by intra- and intermolecular O–H⋯N and OH⋯O hydrogen bonds. Magnetic moments of complexes 2 and 3 at room temperature are characteristic of the high spin Fe(II) and Co(II) compounds. The 1/χM dependences on temperature show weak antiferromagnetic interactions of 2 and 3.
