New Tritopic Terpyridine‐based Fluorescent Probe for the Efficient Determination of Th4+, Zn2+ and F− Ions

Abstract

AbstractThe present work demonstrates the determination of thorium (Th4+), zinc (Zn2+) and fluoride (F−) ions by employing a substituted tripodal terpyridine (TP) as a fluorescence sensor. The distinct fluorescence intensities of the free TP and TP‐M complexes (M=Zn2+or Th4+) with the same emission wavelength at 468 nm were observed in steady‐state photoluminescence (PL) spectra at pH 7.0 with a 1 : 3 ratio of metal to the ligand. A ratiometric dual fluorescence signals for Zn2+ and Th4+ were displayed by the probe TP at varied concentrations. Furthermore, the quantitative determination of F− ions was achieved through the addition of F− to the tripod‐terpyridine‐zinc complex (TP‐Zn2+) where the fluorescence intensity decreases gradually. Notably, the present work facilitates the LOD (limit of detection) as 1.1×10−10 M, 1.01×10−8 M and 3.18×10−10 M and further LOQ (limit of quantification) as 0.37×10−9 M, 0.33×10−7 M and 5.26×10−9 M for Zn2+, Th4+ and F− ions, respectively. The predicted absorption spectra of TP show HOMO to LUMO+2 electronic excitation at 358 nm whereas the complex TP‐Th4+ exhibits HOMO to LUMO+1 electronic excitation at 568 nm.