Design of a Highly Selective Benzimidazole-Based Derivative for Optical and Solid-State Detection of Zinc Ion

A novel series of benzimidazole-based molecules mimicking biological receptors, which exhibit selective coordination with zinc ions, were designed and synthesized. The photochromic behavior of these derivatives with various metal ions suggests a selective interaction of one of the receptors 2-(pyridin-2-yl)-4,7-di(thiophen-2-yl)-3H-benzo[d]imidazole (2c) with zinc ion. The lower limit of detection by photoluminescence quenching was determined to be 16 nM. The mechanism of selective complexation was elucidated by ¹H nuclear magnetic resonance titrations and dynamic light scattering analysis. The stoichiometry of the formation of the Zn(2c)₂ complex was evaluated by single-crystal X-ray diffraction and mass spectral techniques and calculated to be 2:1 (L:M). A change in the electronic energy levels on the sensor analyte interaction was observed by both ultraviolet photoelectron spectroscopy analysis and by density functional theory calculations, suggesting an electroactive semiconductor behavior. A symmetric Schottky structured sensor device was fabricated using the receptor 2c as the active sensing layer. A distinct change in current-voltage characteristics between the receptor and the complex suggests that the fabricated device could be used as a solid-state sensor for detecting zinc ion.

A ratiometric triazine-based colorimetric and fluorometric sensor for the recognition of Zn2+ ions and its application in human lung cancer cells

Herein, we introduce new ratiometric 2,4,6-triamino-1,3,5-triazine-based probes (R1 and R2) having three different binding sites for three metal ion binders, which can selectively detect Zn²⁺ ions and, particularly, the probe R1 strongly interacts with the human lung cancer cell line (A549). Both the probes R1 and R2 are competently selective towards the Zn²⁺ ions with the detection limits of 1.22 × 10^-7 M and 1.13 × 10^-7 M, respectively. The changes in the structure and absorption properties of the probes are explained by density functional theory (DFT) and time dependent density functional theory (TDDFT) calculations. The absorption and fluorescence color change in the solid TLC plate makes it a brilliant Zn²⁺ sensor in a portable form.

Imidazole/benzimidazole-modified cyclotriphosphazenes as highly selective fluorescent probes for Cu2+: synthesis, configurational isomers, and crystal structures

We present a comprehensive work and discuss the fluoroprobe properties of synthesized compounds for copper ion detection with a stereochemical approach using X-ray crystallographic analysis results.

Cd-Cysteine Nanorods as a Fluorescence Sensor for Determination of Fe (III) in Real Samples

A new Cd-Cysteine complex nanorods (Cd-Cys NRs) were synthesized in one step at room temperature, and its morphology, structure and spectral properties were characterized by transmission electron microscopy (TEM), elemental analysis (EA), X-Ray diffraction (XRD), solid state and normal UV-Vis, Fourier transform infrared (FTIR) and spectrofluorometry. The developed Cd-Cys NRs were used as a fluorescence sensor for detection of Fe (III) in different aqueous matrices. The selectivity and sensitivity of the fabricated nano-sensor based on its fluorescence quenching in the presence of Fe (III) were probed according to the Stern-Volmer equation. The detection limit of the method was in micro-molar per liter range. Cd-Cys NRs response tested in different complex samples such as Rosemary plant leaves, exhibited a well-defined response. Anticoagulation measurements were performed to evaluate their blood biocompatibility.

A fluorescence chemosensor based on imidazo[1,2-a]quinoline for Al3+ and Zn2+ in respective solutions

A new and simple chemosensor (L2) Al³⁺ and Zn²⁺ was developed, which show distinctly different optical properties in different solvent systems.