A three-dimensional zinc-based coordination polymer built from 5-carboxyl-ato-1-carboxyl-atomethyl-2-oxidopyridinium with a 4-connected sra topology

摘要

A novel three-dimensional ZnII complex, poly[aqua-(μ4-5-car- boxyl-ato-1-carboxyl-ato-methyl-2-oxido-pyridinium)zinc(II)], [Zn(C8H5NO4)(H2O)] n , has been prepared by hydro-thermal assembly of Zn(CH3COO)2·2H2O and 5-carb-oxy-1-(carb-oxy-methyl)pyridin-1-ium-2-olate (H2ccop). The ccop 2- anions bridge the ZnII cations in a head-to-tail fashion via monodentate aromatic carboxylate and phenolate O atoms to form an extended zigzag chain which runs parallel to the [011] direction. One O atom of the aliphatic carboxylate group of the ccop2- ligand coordinates to the ZnII atom of a neighbouring chain thereby producing undulating layers which lie parallel to the (01 ) plane. A similar parallel undulating planar structure can be obtained if a path involving the other O atom of the aliphatic carboxylate group is considered. Thus, the aliphatic carboxylate group acts in a bridging bidentate mode to give extended -Zn-O-C-O-Zn- sequences running parallel to [001] which link the layers into an overall three-dimensional framework. The three-dimensional framework can be simplified as a 4-connected sra topology with a Schl?fli symbol of 4 2.63.8 if all the ZnII centres and ccop 2- anions are regarded as tetra-hedral 4-connected nodes. The three-dimensional luminescence spectrum was measured at room temperature with excitation and emission wavelengths of 344-354 and 360-630 nm, respectively, at inter-vals of 0.15 and 2 nm, respectively.