SYNTHESES AND STRUCTURAL CHARACTERIZATION OF TWO ZINC COORDINATION POLYMERS COMPOSED OF POLYCARBOXYLATE AND N-DONOR LIGANDS

Two zinc coordination polymers with the formulas [Zn(btec)(0.5)(L-1)](n) (1) and [Zn(4-npa)(L-2)](n) (2) ((L-1 = bis(4-(1H-imidazol-1-yl)phenyl)methanone, L-2 = bis(4-(1H-benzo[d]imidazol-1-yl)phenyl)methanone, 4-H(2)npa = = 4-nitrophthalic acid, H(4)btec = 1,2,4,5-benzenetetracarboxylic acid) are synthesized and structurally characterized. The single crystal X-ray diffraction analysis shows that Zn1 in 1 is four-coordinated by two carboxylate oxygen atoms of two different betc(4-) ligands in a mu(1)-eta(1):eta(0) monodentate coordination mode and two nitrogen atoms from two L-1 ligands to give a slightly distorted tetrahedral coordination geometry. The complex possesses a 4-connected net topology with the point symbol {6(5)center dot 8}. In 2, Zn1 has a distorted tetrahedral geometry with two O atoms from two 4-npa(2-) ligands and two N atoms from two L-2 ligands. The [Zn(4-npa)](2) units are linked with each other by the L-2 ligands to form a 2D network.