Dicarboxylate-controlled three Zn(II) coordination polymers incorporating flexible 1,2-bis(imidazol-1 '-yl)ethane ligand: Syntheses, structures, thermal stabilities and photoluminescent properties

Abstract

Three mixed-ligand Zn(II) coordination polymers (CPs) of the formula {[Zn-2(bime)(2)(adiP)(2)]center dot(H2O)(5)}(n) (1), {[Zn(bime)(ipa)]center dot(H2O)3}(n) (2), {[Zn(bime)(tpa)]center dot(H2O)center dot(CH3OH)](n) (3) (bime = 1,2-bis(imidazol-1'-yl)ethane, H(2)adip = adipic acid, H(2)ipa = isophthalic acid and H(2)tpa = terephthalic acid) were synthesized. All CPs have been characterized by element analysis, powder X-ray diffraction (PXRD), IR and X-ray single-crystal diffraction. Complexes 1 and 2 exhibit similar wavy two-dimensional (2D) sheets with 4(4)-sql topology. Compared tot, complex 2 contains a larger window owing to the different conformation of bime ligand. In both 1 and 2, we observed 1D water chain filling in the 44-sql net. In 3, the bime acts as a bidentate ligand and the tpa adopts a mu(2)-eta(1),eta(1) coordinated mode which links the Zn(II) ions to form a 2D 6(3)-hcb net. The results suggest that the dicarboxylates play crucial roles in the formation of the different structures. In addition, the thermal stabilities and the photoluminescence properties of them were also investigated. (C) 2012 Elsevier B.V. All rights reserved.