Novel one- and two-dimensional Zn(II) coordination polymers based on a versatile 3,6-bis(pyridin-4-yl)phenanthrene-9,10-dione ligand.

Abstract

Two new Zn(II) coordination polymers, namely, catena-poly[[dibromidozinc(II)]-μ-[3,6-bis(pyridin-4-yl)phenanthrene-9,10-dione-κ(2)N:N']], [ZnBr2(C24H14N2O2)]n, (1), and poly[[bromido[μ3-10-hydroxy-3,6-bis(pyridin-4-yl)phenanthren-9-olato-κ(3)N:N':O(9)]zinc(II)] hemihydrate], {[ZnBr(C24H15N2O2)]·0.5H2O}n, (2), have been synthesized through hydrothermal reaction of ZnBr2 and a 60° angular phenanthrenedione-based linker, i.e. 3,6-bis(pyridin-4-yl)phenanthrene-9,10-dione, in different solvent systems. Single-crystal analysis reveals that polymer (1) features one-dimensional zigzag chains connected by weak C-H...π and π-π interactions to form a two-dimensional network. The two-dimensional networks are further stacked in an ABAB fashion along the a axis through C-H...O hydrogen bonds. Layers A and B comprise left- and right-handed helical chains, respectively. Coordination polymer (2) displays a wave-like two-dimensional layered structure with helical chains. In this compound, there are two opposite helical -Zn-HL- chains [HL is 10-hydroxy-3,6-bis(pyridin-4-yl)phenanthren-9-olate] in adjacent layers. The layers are packed in an ABAB sequence and are further connected through O-H...Br and O-H...O hydrogen-bond interactions to form a three-dimensional framework. In (1) and (2), the mutidentate L and HL ligands exhibits different coordination modes.