Zn(II) coordination polymers with flexible V-shaped dicarboxylate ligand: Syntheses, helical structures and properties

Hydrothermal reactions of 2,2'-[hexafluoroisopropylidenebis(p-phenyleneoxy)]diacetic acid (H2L) and zinc ions in the presence of N-donor ancillary ligands afford four novel coordination polymers, namely, [Zn-2(mu(2)-OH)(mu(4)-O)(0.5)(L)] 0.5H(2)O (1), [Zn(L)(2,2'-bipy)(H2O)] (2), [Zn-3(L)(3)(phen)(2)] center dot H2O (3) and [Zn-2(L)(2)(4,4'-bipy)] (4) (2,2'-bipy=2,2'-bipyridine; 4,4'-bipy=4,4'-bipyridine; phen=1,10-phenanthroline). Their structures have been determined by single-crystal X-ray diffraction analyses, elemental analyses, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. Complex 1 shows a 3-D clover framework consisting of [Zn-4(mu(4)-O)(mu(2)-OH)(2)](4+) clusters, and exhibits a novel (3,8)-connected topological net with the Schlafli symbol of {3.4.5}(2){3(4).4(4).5(2).6(6).7(10).8(2)}, and contains double-stranded and two kinds of mesohelices. 2 displays a helical chain structure, which is further extended via hydrogen bonds into a 3-D supramolecular structure with meso-helix chains. 3 displays a 2-D {4(4).6(2)} parallelogram structure, which is further extended via hydrogen bonds into a 3-D supramolecular structure with single-stranded helical chains. 4 shows a 2-D {4(4).6(2)} square structure with left- and right-handed helical chains. Moreover, the luminescent properties of 1-4 have been investigated. (C) 2015 Elsevier Inc. All rights reserved.