Tunable photoluminescence in flexible carboxylate ligand-based coordination polymers with interesting topologies and Fe3+ sensitivity

Abstract

Five new zinc coordination polymers based on flexible carboxylate ligands, namely, [Zn₂(chtc)(H₂O)]·3H₂O (1), [Zn₂(chtc)(4,4′-bpy)_0.5] (2), [Zn(H₂chtc)(bpe)] (3), [Zn(cis-chdc)(bpe)]·3H₂O (4), and [Zn(trans-chdc)(bpe)(NO₃)(H₂O)]·H₂O (5) (chtc/H₂chtc = deprotonated/half-protonated cyclohexane-1e,2a,4a,5e-tetracarboxylic acid, cis/trans-chdc = cyclohexane-1e,2a/1e,2e-dicarboxylic acid, 4,4′-bpy = 4,4′-bipyridine, bpe = trans-1,2-(bis(4-pyridyl)ethene)) have been constructed and characterized. Owing to the tunability of linking ligands, these complexes show different interesting topological networks, namely uninodal umc three-dimensional network for 1, mtc three-dimensional non-manifold topology for 2, (4,4) net for the two-dimensional structure of 3, dmp-c interpenetrated network for 4, and one-dimensional ladder chain for 5. Notably, all complexes exhibit selectivity and sensitivity for Fe³⁺ ions with detection limit of less than 3.5 μM, which was correlated to the dimensionalities of the structures, implying their potential application in sewage detection.