Rhodamine-based turn-on fluorescent and colorimetric chemosensor for selective Pb2+ detection: insights from crystal structure, molecular docking, real sample analysis, and logic gate applications†
Ram Kumar, Bholey Singh, Rita Kakkar, Avneesh Mittal and Balaram Pani
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引用次数: 0
Abstract
Lead (Pb2+) contamination remains a critical environmental and public health concern, necessitating its effective detection methods. In this study, we report the design and synthesis of a novel rhodamine-based Schiff base chemosensor (L), which demonstrates high selectivity and sensitivity for Pb2+ ions. The chemosensor exhibited distinct colorimetric and fluorescence responses, providing a practical and efficient approach for detecting Pb2+ in environmental and biological samples. Upon interaction with Pb2+ ions in acetonitrile, the sensor exhibited a distinct turn-on fluorescence response along with a noticeable colour change. The binding studies confirmed that sensor L bound to lead ions in a 1 : 1 ratio. This was determined using Job's plot and Benesi–Hildebrand (B–H) plot analyses, which also revealed a binding constant (Ka) of 0.954 × 104 that indicated strong and specific interaction between L and Pb2+ ions. The limit of detection was found to be 3.77 nM for Pb2+ ions, demonstrating the remarkable sensitivity of the sensor. DFT calculations confirmed the stability of L–Pb2+ complex, where Pb2+ was coordinated to three atoms of L. Molecular docking analyses of L with human DNA (5VBN) indicated a binding affinity of −5.7 kcal mol−1, highlighting its potential for DNA interactions and therapeutic use. The successful detection of Pb2+ in real water samples, solid-state sensing experiments, and filter paper-based assays demonstrated the practical applications of the sensor, highlighting its effectiveness in environmental monitoring.