Effective recognition of multiple anions by an azobenzene-Al3+ system

摘要

A ready-to-use multifunctional coordinative system, 2,2'-dihydroxyazobenzene-aluminum (III) (DHAB-Al3+), was created to recognize several anions effectively through three channels, namely colorimetric detection, UV-Vis spectroscopy, and fluorescence spectroscopy. Under naked eye visualization, the H2PO4- can be readily distinguished from the other anions by the DHAB-Al3+ system through a change in color from reddish-orange to light yellow. H2PO4-, was qualitatively detected by using UV-Vis and fluorescence spectra. Differentiating SO32-, HPO42-, and HCO3- anions colorimetrically is difficu thus, CO32-, SO32-, HPO42-, and HCO3- were discriminated by adopting distinct changes in the UV-Vis spectra. CO32-, HPO42-, and HCO3- were accurately quantified using fluorescence spectra. The DHAB-Al3+ system responded to H2PO4-, and CO32- via a sensing mechanism based on a displacement approach. By contrast, the system responded to SO32, HPO42, and HCO3 based on a binding site signaling subunit approach. The DHAB-Al3+ system can determine the concentration ranges of H2PO4-, with the naked eye and quantify CO32-, SO32-, HPO42-, and HCO3- through UV-Vis spectra.