A 4'-(4-carboxyphenyl)-3,2':6',3''-terpyridine-based luminescent cadmium(II) coordination polymer for the detection of 2,4,6-trinitrophenol

Abstract

The title coordination polymer, poly[bis[μ3-4-(3,2':6',3''-terpyridin-4'-yl)benzoato]cadmium(II)], [Cd(C₂₂H₁₄N₃O₂)₂]_n or [Cd(3-cptpy)₂]_n, (I), has been synthesized solvothermally and characterized by IR spectroscopy, thermogravimetric analysis, and single-crystal and powder X-ray diffraction. The structure is composed of 3-cptpy^- ligands bridging Cd atoms, with each Cd atom coordinated by six ligands and each ligand coordinating to three Cd atoms. Each Cd atom is in a slightly distorted trans-N₂O₄ octahedral environment, forming a two-dimensional layer structure with a (3,6)-connected topology. Layers are linked to each other by π-π stacking, resulting in a three-dimensional supramolecular framework. The strong luminescence and good thermal stability of (I) indicate that it can potentially be used as a luminescence sensor. The compound also shows a highly selective and sensitive response to 2,4,6-trinitrophenol through the luminescence quenching effect.

Keywords: TNP sensor; cadmium(II); crystal structure; luminescence; two-dimensional coordination polymer.