Ditopic Carboxylate Containing Zigzag Chain Polymers with Tetrahedral Co(II) and Zn(II) Nodes

Two 1D coordination polymers based on tetrahedral cobalt(II) and zinc(II) complex monomers involving terephthalate (1,4-benzenedicarboxylate) dianions as ligand bridges viz., [Co(ta)(DMP)2]n 1 and [Zn(ta)(DMP)2.H2O]n 2 (ta = terephthalate, DMP = 3,5-dimethylpyrazole) have been synthesized and characterized by elemental analysis, spectroscopic methods as well as by single crystal X-ray diffraction method. Compounds 1 and 2 are chain polymers wherein the polymeric zigzag chains remain linked through intermolecular hydrogen bonds to give rise to robust 3D network structures. Topological analysis of the structure of 2 reveals an underlying net that can be described as 2C1. While the solid state UV–vis–NIR spectrum 2 reflects the tetrahedral coordination geometry around Co(II), thermogravimetric studies indicate that this species retains its 3D network up to about 170 °C. The temperature dependence of the magnetic susceptibility of 1 indicates weak antiferromagnetic interaction among the unpaired spins.