Design and synthesis of a terbium(III) complex-based luminescence probe for time-gated luminescence detection of mercury(II) ions

Preparation of a DNA-Tb-MOF conjugate as a time-resolved probe for the detection of SO2 derivatives through an off-on effect

Herein we synthesize a DNA-sensitized Tb-MOF conjugate (DNA-Tb-MOF) as a time-resolved luminescent probe to sensitively and selectively assay SO₂ and their derivatives (i.e., HSO₃^-) through a photoluminescence off-on effect. The charge and energy transfer mechanism enables the demonstration of the effect of the photoluminescence turn-on which results from the reaction between the amino group of the DNA-Tb-MOF conjugate and SO₂/HSO₃^-. The results demonstrate that the DNA-Tb-MOF conjugate probe can sense SO₂ and their derivatives (i.e., HSO₃^-) with a detection limit of 0.02 ppm. Moreover, the photoluminescence off-on effect can be observed even by the naked eye.

Ratiometric Fluorescent Nanoprobe for Highly Sensitive Determination of Mercury Ions

In this study, a novel dual-emission ratiometric fluorescent nanoprobe (RFN) was synthesized and ultilized for highly sensitive determination of mercury ions. In this nanoprobe, fluorescein isothiocyanate (FITC) doped silica (SiO₂) served as a reference signal, FITC–SiO₂ microspheres were synthesized and modified with amino groups, and then Au Nanoclusters (AuNCs) were combined with the amino groups on the surface of the FITC–SiO₂ microspheres to obtain the RFN. The selectivity, stability, and pH of the RFN were then optimized, and the determination of mercury ions was performed under optimal conditions. The probe fluorescence intensity ratio (F₅₂₀ nm/F₆₈₀ nm) and Hg²⁺ concentration (1.0 × 10⁻¹⁰ mol/L to 1.0 × 10⁻⁸ mol/L) showed a good linear relationship, with a correlation coefficient of R² = 0.98802 and a detection limit of 1.0 × 10⁻¹⁰ mol/L, respectively. The probe was used for the determination of trace mercury ion in water samples, and the recovery rate was 98.15~100.45%, suggesting a wide range of applications in monitoring pollutants, such as heavy metal ion and in the area of environmental protection.

A novel and ultrasensitive yellow to taupe brown colorimetric sensing and removal method for Hg(ii) based on the thermosensitive poly(N-isopropyl acrylamide) stabilized silver nanoparticles

AgNP/PNIPAm was developed as a dual-functional colorimetric probe and removal system for Hg²⁺.

A selective naked-eye chemosensor derived from 2-methoxybenzylamine and 2,3-dihydroxybenzaldehyde - synthesis, spectral characterization and electrochemistry of its bis-bidentates Schiff bases metal complexes

A new colorimetric receptor HL, acting as a bidentate Schiff base ligand, has been synthesized by condensation of 2-methoxybenzylamine on 2,3-dihydroxybenzaldehyde in a methanolic solution. Interestingly, this chelating agent can selectively detect Cu²⁺, Co²⁺, Fe²⁺ and Fe³⁺ ions with a simple and an easy-to-make, well defined naked-eye visible color changes in two different solvents like acetonitrile and methanol. This bidentate ligand coordinates three metal ions of Co(II), Cu(II) and Fe(II) via nitrogen and oxygen atoms. The molecular structures of the synthesized compounds were elucidated by various physicochemical properties such as the elemental analysis, FT-IR, HNMR, UV-Vis and the Mass spectrometry. The resulting general formulae [M(L)₂·H₂O] (M(II)=Cu, Fe, Co) are proposed as mononuclear complexes. The solvatochromism properties of these compounds were studied with their absorption spectra using different solvents as methanol (MeOH), acetonitrile (AN), tetrahydrofuran (THF), dimethylformamid (DMF), dimethylsulfoxid (DMSO) and dichloromethane (DC). The Electrochemical behavior of copper complex was explored in DMF solutions by cyclic voltammetry (CV) with two working electrodes: glassy carbon (GC) and platinum electrode (Pt). This study reveals that copper complex shows successively two redox systems as Cu^III/II and Cu^II/I. The Fe^III/II and Co^II/I redox systems have also been studied in DMF and DMSO media.

Exploitation and application of a highly sensitive Ru(II) complex-based phosphorescent chemodosimeter for Hg2+ in aqueous solutions and living cells

A novel Ru(II) complex-based phosphorescent probe Rubpy-1 was designed and synthesized conveniently by incorporating of chemodosimeter into the luminophor, which exhibits good water solubility, longer excitation wavelength, and rapid turn-on phosphorescent response only toward Hg(2+) in aqueous system under physiological pH. The spectral response mechanism and Hg(2+)-promoted structure change of the chemodosimeter were analyzed in detail by theoretical calculations and electrospray ionization mass spectrometry. When time-resolved photoluminescence techniques were used, the Rubpy-1 could eliminate effectively the signal interference from the short-lived background fluorescence in complicated media, accompanied by the significant improvement of the signal-to-noise ratio and the accuracy of the detection. Furthermore, Rubpy-1 showed low cytotoxicity and excellent membrane permeability toward living cells, which was successfully applied to monitor intracellular Hg(2+) effectively by confocal luminescence imaging.

Design and application of a water-soluble phosphorescent Ru(ii) complex as turn-on sensing material for Hg2+

A turn-on Ru(ii)-based phosphorescent chemodosimeter for Hg²⁺ is designed by introducing Hg²⁺-promoted desulfurization and intramolecular cyclic guanylation of thiourea reaction into the luminophor.