Azaneylylidene-based tetradentate Schiff base as a new "ON-OFF" fluorescent probe for the detection of Cu(II) ion: Synthesis, characterization and real sample analysis

N R Divyashree; H D Revanasiddappa; N R Bhavya; M Mahendra; B Jayalakshmi; Chandan Shivamallu; Shiva Prasad Kollur

doi:10.1016/j.saa.2023.122435

Azaneylylidene-based tetradentate Schiff base as a new "ON-OFF" fluorescent probe for the detection of Cu(II) ion: Synthesis, characterization and real sample analysis

Spectrochim Acta A Mol Biomol Spectrosc. 2023 May 5:292:122435. doi: 10.1016/j.saa.2023.122435. Epub 2023 Feb 3.

Authors

N R Divyashree¹, H D Revanasiddappa², N R Bhavya³, M Mahendra⁴, B Jayalakshmi⁵, Chandan Shivamallu⁶, Shiva Prasad Kollur⁷

Affiliations

¹ Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru, Karnataka 570 006, India.
² Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru, Karnataka 570 006, India. Electronic address: revanasiddappa1066@gmail.com.
³ Department of Studies in Physics, University of Mysore, Manasagangotri, Mysuru, Karnataka 570 006, India; Department of Studies in Physics, Vidyavardhaka College of Engineering, Mysore, 570 002 Karnataka, India.
⁴ Department of Studies in Physics, University of Mysore, Manasagangotri, Mysuru, Karnataka 570 006, India.
⁵ Department of Botany, Government College for Women (Autonomous), Mandya 571 401, Karnataka, India.
⁶ Department of Biotechnology and Bioinformatics, School of Life Sciences, JSS Academy of Higher Education & Research, Myuru 570015, Karnataka, India.
⁷ School of Physical Sciences, Amrita Vishwa Vidyapeetham, Mysuru Campus, Mysuru, Karnataka 570 026, India.

PMID: 36758319
DOI: 10.1016/j.saa.2023.122435

Abstract

Herein we describe the synthesis of Cu²⁺ sensor, 2,2'-((1E,1'E)-((4-chloro-1,2-phenylene)bis(azaneylylidene))bis(methane-ylylidene))bis(4-bromophenol) (CPMB) and characterization using various spectral and analytical techniques. CPMB exhibited high selectivity towards Cu²⁺ ions via fluorescence quenching mechanism, which combined the character of high selectivity towards Cu²⁺ assay even in the presence of other common metal ions such as Cu²⁺, Al³⁺, Co²⁺, Ni²⁺, Mn²⁺, Zn²⁺ Pb²⁺ Cd²⁺, Fe²⁺, Hg²⁺, Mg²⁺ and Fe³⁺ (30 μM) ethanol-water (1:9 v/v) system. Upon the addition of the solution of Cu²⁺ ions to CPMB, the complexation of Cu²⁺ with CPMB leads to the immediate formation of light green color, indicating that CPMB can act as simple colorimetric sensor, particularly for Cu²⁺ in the presence of most interfering metal ions in ethanol-water medium. More interestingly, the ability of sensing behavior of CPMB for Cu²⁺ ion in the real water samples (tap water and lake water samples) was also investigated. Further, Job's plot confirmed that the complexation occurred in 1:1 ratio (ligand:metal). Furthermore, the fluorescence inhibiting factor showed a good linear relationship with the concentration of Cu²⁺ with detection limit of 0.302 μM. The electronic transitions of the complex in ethanol were studied using DFT calculations.

Keywords: Chemosensor; Cu(II) ion; DFT; Fluorescence quenching.