A rapid turn-on dual functional rhodamine B probe for aluminum (III) and copper (II) that can be utilised as a molecular logic gate and in water analysis

The new sensor, R34 was prepared from the reaction of rhodamine B hydrazide and 3,4-dihydroxybenzaldehyde, and it was characterised by spectroscopic techniques and single crystal X-ray diffraction. Sensor R34 can detect Al3+/Cu2+ through colorimetric and fluorometric methods in MeCN solution, which displayed a notable color change from colorless to pink in the presence of Al3+ and colorless to orange for Cu2+. Other than that, both Al3+/Cu2+ caused orange fluorescence enhancement under UV-light. Besides, sensor R34 demonstrates good selectivity and sensitivity towards Al3+/Cu2+ with high association constant (K-a > 10(4) M-1) and limit of detection down to the nano molar level. The reversibility of the sensor is verified by using EDTA and the finding implies that probe R34 can be recycled. Moreover, binding mechanism of the metal complexes were studied through DFT calculations, Job's plot, H-1 NMR and FT-IR spectroscopy. Using Al3+/Cu2+ and EDTA as chemical inputs and absorption signal at 560 nm as output, sensor R34 can be applied as an INHIBIT logic gate at molecular level. In addition, sensor R34 was examined for the ability to trace Al3+/Cu2+ in two different water samples. Furthermore, cytotoxicity of the sensor towards CCD-18Co and HT-29 cell lines was evaluated with MTT assay. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

A new sensor, R34, was developed for the detection of Al3+/Cu2+ using colorimetric and fluorometric methods. The sensor exhibited high selectivity, sensitivity, and reversibility, and could be used as a molecular-level logic gate. Additionally, the sensor's cytotoxicity towards cell lines was evaluated.