TWO COORDINATION POLYMERS INDUCED BY TRANSITION METAL Zn(II) AND Co(II) IONS BASED ON 3-NITROBENZENE-1,2- DICARBOXYLIC ACID AND 3,5-BIS(1- IMIDAZOLYL)PYRIDINE LIGANDS

Two new coordination polymers, {[Zn(3-Nbdc)(bip)]·2H 2 O} n ( 1 ) and {[Co(3-Nbdc)(bip)(H 2 O)]0.25H 2 O} n ( 2 ) (H 2 3-Nbdc = 3-nitrobenzene-1,2-dicarboxylic acid, bip = 3,5-bis(1-imidazolyl)pyridine) were synthesized under the hydrothermal conditions and characterized by single crystal X-ray diffraction and elemental analysis. In 1 , the Zn(II) ion forms a slightly distorted [ZnO 2 N 2 ] tetrahedron by two carboxylate oxygen atoms and two nitrogen atoms. Adjacent Zn(II) neighbors are linked by 3-Nbdc dianions adopting monodentate coordination mode to form 1D Zn-carboxylate chain, which is further extended by bip molecules to produce a two-dimensional thick layer. For complex 2 , two six-coordinated Co(II) ions with different coordination environments are alternately connected by 3-Nbdc dianions and bip ligands along different directions to generate a two-dimensional grid layer. Furthermore, Powder X-ray diffractions, FTIR spectra and thermogravimetric analyses are also investigated.