Structure characterization and physical properties of a complex with supramolecular architectures Co₂(2,6-DPC)₂Co(H ₂O)₅·2H₂O (DPC=2,6- pyridinedicarboxylate)

Reaction of 2,6-pyridinedicarboxylic with CoCl₂·6H ₂O in aqueous solution give rise to a three-dimensional complex Co₂(2,6-DPC)₂Co(H₂O)₅·2H ₂O (DPC=2,6-pyridinedicarboxylate) 1. It has been characterized by elemental analyses, infrared spectra (IR) spectrum, thermogravimetric (TG) analysis, EPR spectrum, and single crystal X-ray diffraction. The complex crystallizes in the P2(1)/c space group with a=8.3906(3)Å, b=27.4005(8)Å, c=9.6192(4)Å, α=90.00°, β=98.327(2)°, γ=90.00°, V=2188.20(14)ų, Z=4. There are two types of cobalt environments: Co(1) is coordinated by four oxygen atoms from four carboxyl groups and two nitrogen atoms which are all from pdc². Co(2) is coordinated by six oxygen atoms, five from coordinated water molecules and one from a carboxyl of pdc²- of which the other oxygen atom is linked to the Co(1). The extensive intermolecular hydrogen bonds are formed in the crystal by means of the five coordinated water molecules. Thus the complex is extended into a three-dimensional network with the aid of hydrogen bonds. In addition, The compound of 1 exhibited significant paramagnetic signals with the value of g=2.03.