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

Abstract Hydrothermal reactions of 2,2′-[hexafluoroisopropylidenebis(p-phenyleneoxy)]diacetic acid (H 2 L) and zinc ions in the presence of N-donor ancillary ligands afford four novel coordination polymers, namely, [Zn 2 ( μ 2 -OH)( μ 4 -O) 0.5 (L)]·0.5H 2 O ( 1 ), [Zn(L)(2,2′-bipy)(H 2 O)] ( 2 ), [Zn 3 (L) 3 (phen) 2 ]·H 2 O ( 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 ( µ 4 -O)( µ 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 meso-helices. 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.