A Multimode fluorescent sensor for sequential detection of Cu2+ and cysteine as well as pH sensor with real sample Applications: Extensive experimental and DFT studies

Alam Shabbir; Sohail Anjum Shahzad; Abdullah Yahya Abdullah Alzahrani; Zulfiqar Ali Khan; Muhammad Yar; Waqar Rauf

doi:10.1016/j.saa.2024.125414

A Multimode fluorescent sensor for sequential detection of Cu²⁺ and cysteine as well as pH sensor with real sample Applications: Extensive experimental and DFT studies

Spectrochim Acta A Mol Biomol Spectrosc. 2025 Feb 15:327:125414. doi: 10.1016/j.saa.2024.125414. Epub 2024 Nov 9.

Authors

Alam Shabbir¹, Sohail Anjum Shahzad², Abdullah Yahya Abdullah Alzahrani³, Zulfiqar Ali Khan⁴, Muhammad Yar⁵, Waqar Rauf⁶

Affiliations

¹ Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, University Road, Abbottabad 22060, Pakistan.
² Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, University Road, Abbottabad 22060, Pakistan. Electronic address: sashahzad@cuiatd.edu.pk.
³ Department of Chemistry, Faculty of Science and Arts, King Khalid University, Mohail Assir, Saudi Arabia.
⁴ Department of Chemistry, Government College University Faisalabad, Faisalabad 38000, Pakistan.
⁵ Interdisciplinary Research Center in Biomedical Materials (IRCBM), COMSATS University Islamabad, Lahore Campus, Defence Road off Raiwind Road, Lahore 54000, Pakistan.
⁶ Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad 38000, Pakistan.

PMID: 39550819
DOI: 10.1016/j.saa.2024.125414

Abstract

Highly responsive and optically selective (E)-1-((4-phenoxyphenyl) diazenyl)naphthalen-2-ol) sensor PDN with aggregation induced emission enhancement (AIEE) properties has been developed for the sequential detection of Cu²⁺ and L- Cysteine through fluorescence On-Off-On strategy. The selectivity of sensor depends on the presence of a diazo functional group and its appropriate cavity location in sensor molecule. Azo dye-based (E)-1-((4-phenoxyphenyl) diazenyl)naphthalen-2-ol) sensor PDN has been synthesized by utilizing a simple diazotization synthetic methodology that showed extraordinary AIEE behavior with bathochromic shift owing to the formation of J-aggregates. The morphology and size of aggregates were analyzed by SEM and DLS analysis, respectively. The calculated LOD of sensor PDN for Cu²⁺, and L-cysteine is 0.113 nM, and 84 nM, respectively. Fluorescence, UV-visible, LC-MS, ¹H and ¹³C NMR titration were carried out to understand the interaction of sensor with Cu²⁺. The sensor was practically utilized in the sequential sensing of Cu²⁺ and Cys in real samples. Interestingly, sensor PDN was successfully employed for the sensing of a strong acid and base as well as the detection of Cu²⁺ ions in the solid state. Moreover, these experimental results were supported through DFT calculations.

Keywords: Aggregation induced emission; Detection of cysteine; Multimode fluorescent sensor; Sequential detection of Cu(2+); Solid state detection; pH sensor.