Ligand geometry-driven formation of different coordination polymers from Zn(NO3)(2), 1,4-bpeb and phenylenediacetic acids

The hydrothermal reactions of Zn(NO3)(2)center dot 6H(2)O with 1,4-bis[2-(4-pyridyl)ethenyl]benzene (1,4-bpeb), NaOH, and 1,4-phenylenediacetic acid (1,4-H(2)PDA), 1,3-phenylenediacetic acid (1,3-H(2)PDA) or 1,2-phenylenediacetic acid (1,2-H(2)PDA) afforded three coordination polymers {[Zn(1,4-PDA)(1,4-bpeb)]center dot 2H(2)O}(n) (1), [Zn(1,3-PDA)(1,4-bpeb)](n) (2) and [Zn-4(mu-OH)(2)(1,2-PDA)(3)(1,4-bpeb)(2)](n) (3), respectively. All these compounds were characterized by elemental analysis, IR, powder X-ray diffraction, and single-crystal X-ray diffraction. 1 exhibits a five-fold interpenetrating 3D diamondoid framework constructed by linking Zn atoms with trans-1,4-PDA and trans-trans-trans-1,4-bpeb ligands. 2 has a 2D (4,4) network formed by connecting dinuclear [Zn-2(1,3-PDA)(2)] (1,3-PDA serving as a trans conformation) units with trans-cis-trans-1,4-bpeb ligands. 3 could be considered as a 2D 5-connected network derived from linking tetranuclear [Zn-4(mu-OH)(2)(1,2-PDA)(3)] (1,2-PDA acting as cis and trans conformations) units via trans-cis-trans-1,4-bpeb bridges. The results provided some insight into the ligand geometry-driven assembly of coordination polymers. Thermal stability and photoluminescent properties of 1-3 were also investigated.