Zinc(II) and cadmium(II) coordination polymers containing phenylenediacetate and bis(imidazol-1-ylmethyl)benzene linkers: The effect of ligand isomers on the solid state structures

This work presents a systematic investigation of the reactions of o-, m- and p-phenylenediacetic acid with Zn(II)/Cd(II) salts in the presence of different semi-rigid o-, m- and p-bis(imidazol-1-ylmethyl)benzene co-ligands. Fourteen new coordination polymers - {[Zn(mu-opda)(mu-mbix)]center dot 0.5H(2)O}(n) (1), {[Zn(mu-mpda)(mu-obix)]center dot H2O}(n) (2), {[Zn-2(mu-mpda)(2)(mu-mbix)(2)]center dot 5H(2)O}(n) (3), {[Zn(mu-mpda)(mu-mbix)]center dot 2H(2)O}(n) (4), {[Zn(mu-mpda)(mu-pbix)]center dot 0.5H(2)O}(n) (5), [Zn(mu-ppda)(mu-obix)](n) (6), {[Zn(mu-ppda)(mu-mbix)]center dot 0.5H(2)O}(n) (7), {[Zn(mu-ppda)(mu-pbix)]center dot H2O center dot DMF}(n) (8), {[Cd(mu-mpda)(mu-obix)(1.5)]center dot H2O}(n) (9), {[Cd(mu-mpda)(mu-obix)]center dot H2O}(n) (10), {[Cd(mu-mpda)(mu-mbix)(H2O)]center dot H2O}(n) (11), [Cd(mu(3)-ppda)(mu-obix)](n) (12), [Cd(mu(3)-ppda)(mu-mbix)](n) (13) and [Cd(mu(3)-ppda)(mu-pbix)](n) (14) (o/m/ppda=1,2/1,3-/1,4-phenylenediacetate, o/m/pbix=1,2-/1,3-/1,4-bis(imidazol-1-ylmethyl) benzene) - have been prepared and structurally characterized. Two of the complexes were found to possess one-dimensional (1D) structures, eleven complexes were found to be two-dimensional (2D) coordination networks and one of the complexes was found to be a three-dimensional (3D) coordination network. Of the 1D structures, 3 forms nanotubes, whereas in 8 pairs of pbix ligands bridge the zinc(II) centers to generate Zn-2(pbix)(2) dimers, which in turn are linked together by pairs of ppda linkers to give chains. Compound 5 contains a 4-fold interpenetrated 3D framework. The structure of 10 contains interpenetrated 2D frameworks, leading to a three-dimensional gross structure. The thermal stabilities and luminescent properties for 1-14 are also reported.