Assembly of two novel coordination polymers by selecting ditopic or chelating auxiliary ligands with naphthalene-2,6-dicarboxylic acid: synthesis, structure and luminescence sensing

Abstract

The Fe^III ion as a ubiquitous metal plays a key role in biochemical processes. Iron deficiency or excess in the human body can induce various diseases. Thus, effective detection of the Fe^III ion has been deemed an issue of focus. To develop more crystalline chemical sensors for the selective detection of Fe³⁺, two novel two-dimensional (2D) coordination polymers, namely, poly[[[μ-bis(pyridin-4-yl)amine-κ²N:N'](μ-naphthalene-2,6-dicarboxylato-κ²O²:O⁶)zinc(II)] 0.5-hydrate], {[Zn(C₁₂H₆O₄)(C₁₀H₉N₃)]·0.5H₂O}_n, 1, and poly[(4,4'-dimethyl-2,2'-bipyridine-κ²N,N')(μ-naphthalene-2,6-dicarboxylato-κ²O²:O⁶)hemi(μ-naphthalene-2,6-dicarboxylic acid-κ²O²:O⁶)copper(II)] [Cu(C₁₂H₆O₄)(C₁₂H₁₂N₂)(C₁₂H₈O₄)_0.5]_n, 2, have been prepared using solvothermal methods. Single-crystal X-ray diffraction analysis shows that compound 1 is an undulating twofold interpenetrated 2D (4,4)-sql network and compound 2 is a twofold interpenetrated 2D honeycomb-type network with a (6,3)-hcb topology. In addition, 1 exhibits highly selective sensing for the Fe³⁺ ion.

Keywords: bipyridine; crystal structure; luminescence sensing; naphthalene-2,6-dicarboxylic acid; porous material; two-dimensional coordination polymer; twofold interpenetrating network.