A fluorescent probe for detection of Hg2+ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene

Abstract

In this paper, tetramethyl cucurbit[6]uril (TMeQ[6]) and 1,2-bis(4-pyridyl)ethene (G) were used to construct a supramolecular fluorescent probe G@TMeQ[6]. The host-guest interaction between TMeQ[6] and G was investigated using ¹H NMR spectroscopy, single-crystal X-ray diffraction and various experimental techniques. The results show that TMeQ[6] and G form an inclusion complex with a host-guest ratio of 1:1 and the equilibrium association constant (K_a) was 2.494 × 10⁴ M^-1. The G@TMeQ[6] fluorescent probe can sensitively recognize Hg²⁺ ions by fluorescence enhancement. The linear range is 0.33 × 10^-5-1.65 × 10^-5 mol·L^-1, R² = 0.9926, and the limit of detection is 4.12 × 10^-8 mol·L^-1. The fluorescent probe can be used to detect the concentration of Hg²⁺ ions in aqueous solution, and provides a theoretical basis for the development of new fluorescent probes for detecting heavy metal ions.

Keywords: 1,2-bis(4-pyridyl)ethane; Hg2+ ion recognition; fluorescent probe; host–guest chemistry; tetramethyl cucurbit[6]uril.