A rhodamine based chemosensor for solvent dependent chromogenic sensing of cobalt (II) and copper (II) ions with good selectivity and sensitivity: Synthesis, filter paper test strip, DFT calculations and cytotoxicity

• Main Authors: Chan, Wei Chuen, Saad, Hazwani Mat, Sim, Kae Shin, Lee, Vannajan Sanghiran, Ang, Chee Wei, Yeong, Keng Yoon, Tan, Kong Wai
• Format: Article
• Published: Elsevier 2021
• Subjects: Q Science (General); QD Chemistry
• Online Access: http://eprints.um.edu.my/28560/
• Institution: Universiti Malaya

A new chemosensor 1 was synthesized by reacting rhodamine B hydrazide and 2,3,4-trihydroxybenzaldehyde, which was then characterized by spectroscopic techniques and single crystal X-ray crystallography. Sensor 1 has the ability to sense Co2+/Cu2+ ions by ``naked-eye'' with an apparent colour change from colourless to pink in different solvent system, MeCN and DMF respectively. Furthermore, it can selectively detect Co2+/Cu2+ among wide range of different metal ions, and it exhibits low detection limit of 4.425 x 10(-8) M and 1.398 x 10(-7) M respectively. Binding mode of the two complexes were determined to be 1:1 stoichiometry for Co2+ complex and 1:2 stoichiometry for Cu2+ complex through Job's plot, IR spectroscopy, mass spectrometry and H-1 NMR spectroscopy. Moreover, reversibility of the sensor 1 as copper (II) ion detector was determined by using EDTA and the results showed that sensor 1 can be reused for at least 6 cycles. Other than that, a low cost chemosensor test strips were fabricated for the convenient ``naked-eye'' detection of Co2+ and Cu2+ in pure aqueous media. The MTT assay was conducted in order to determine the cytotoxicity of sensor 1 towards human cell lines. (C) 2021 Elsevier B.V. All rights reserved.