Terpyridine-Based Sensors for Metal Ion Detection: High Sensitivity, Selectivity, and Computational Analysis of Binding Mechanisms

In this study, new terpyridine ligands (1 and 2) were synthesized and their potential as chemosensor was investigated. Firstly, structural and optical characterization of the newly synthesized compounds 1 and 2 were performed by NMR, HRMS analyses, UV-vis. absorption and fluorescence spectrophotometer. To the best of our knowledge, the novelty of this study lies in the exceptional chemosensor potential demonstrated by our synthesized compounds, surpassing those reported in the literature. Solvent-dependent optical behavior was explored in thirteen different solvents, identifying ethanol as the optimal medium for sensor studies. The ion selectivity of 1 and 2 was examined against 20 different metal cations, revealing that compound 1 functions as a colorimetric sensor for Fe2+ and Fe3+, while compound 2 acts as a colorimetric sensor for both Fe2+, Fe3+ and Cr3+ and a fluorometric sensor for Zn2+ and Cd2+. With compound 1, the detection limits for Fe2+, Fe3+ were determined as 0.18 and 1.41 mu M, respectively, and with compound 2, the detection limits for Fe2+, Fe3+, Cr3+, Zn2+ and Cd2+ were determined as 2.22, 0.22, 11.63, 0.31 and 2.50 mu M, respectively. Both sensors demonstrated high selectivity and minimal interference from other cations. Furthermore, reversibility studies with EDTA confirmed the regenerative sensing ability of 2 for Zn2+ and Cd2+ detection. The binding mechanisms of compounds 1 and 2 with the detected ions (Fe2+, Fe3+, Cr3+, Zn2+ and Cd2+) were determined by FTIR measurements. Moreover, the validation of the detecting capabilities of chemosensors 1 and 2 is obtained using Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations, utilizing FMO and UV-Vis analyses to gain insights into their electronic structures and photophysical properties. The experimental findings were supported by computational studies, elucidating the electronic transitions and binding mechanisms. These findings indicate that the synthesized terpyridine-based chemosensors have significant potential for metal ion detection in analytical and environmental applications.

Journal

JOURNAL OF INORGANIC AND ORGANOMETALLIC POLYMERS AND MATERIALS

Year

2025

Volume

35

Issue

12

Pages

9958-9984

ISSN

1574-1443

eISSN

1574-1451

DOI

10.1007/s10904-025-03893-3

WoS UID

WOS:001510294700001