Stable Zinc(II) Coordination Polymer as a Rapid and Highly Sensitive Fluorescence Sensor for the Discriminative Sensing of Biomarker 2-(2-Methoxyethoxy) Acetic Acid.

Abstract

A novel two-dimensional bilayer Zn-based luminescent coordination polymer (LCP) [Zn2(μ2-OH)(4-dptp)(3,4',5-bpt)] (LCP 1) [4-dptp = N3,N4-bis(pyridin-4-ylmethyl)thiophene-3,4-dicarboxamide and 3,4',5-H3bpt = biphenyl-3,4',5-tricarboxylic acid] was successfully prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR spectroscopy, powder X-ray diffraction, and luminescence spectroscopy. LCP 1 displayed excellent fluorescence-quenching efficiency toward a biomarker 2-(2-methoxyethoxy) acetic acid (MEAA) with a high Ksv (5.153 × 104 M-1), a low limit of detection (0.244 μM), and a rapid response time (28 s). Additionally, LCP 1 can repeatedly detect MEAA at least eight times with excellent stability. The sensing mechanism was also carefully investigated through UV-vis absorption spectroscopy, density functional theory calculations, and fluorescence lifetime analysis.