Molecular recognition of carbonate ion using a novel turn-on fluorescent probe

Hardeep Kaur; Riya; Amandeep Singh; Harpreet Singh; Uma Ranjan Lal; Ashutosh Kumar; M V N L Chaitanya

doi:10.1016/j.saa.2023.123270

Molecular recognition of carbonate ion using a novel turn-on fluorescent probe

Spectrochim Acta A Mol Biomol Spectrosc. 2023 Dec 15:303:123270. doi: 10.1016/j.saa.2023.123270. Epub 2023 Aug 18.

Authors

Hardeep Kaur¹, Riya², Amandeep Singh³, Harpreet Singh⁴, Uma Ranjan Lal⁵, Ashutosh Kumar⁶, M V N L Chaitanya⁷

Affiliations

¹ Post Graduate Department of Chemistry, Khalsa College Amritsar, Punjab 143102, India. Electronic address: hardeepchem@gmail.com.
² Post Graduate Department of Chemistry, Khalsa College Amritsar, Punjab 143102, India.
³ Department of Pharmacognosy and Phytochemistry, Khalsa College of Pharmacy, Amritsar, Punjab 143102, India. Electronic address: amandeepkcp@gmail.com.
⁴ Department of Chemistry, University of California, Berkeley, CA 94720, USA.
⁵ Department of Natural Product, National Institute of Pharmaceutical and Education Research, Mohali, Punjab 160062, India.
⁶ Department of Pharmacology and Toxicology, National Institute of Pharmaceutical and Education Research, Mohali, Punjab 160062, India.
⁷ Department of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab 144411, India.

PMID: 37611524
DOI: 10.1016/j.saa.2023.123270

Abstract

A novel turn-on fluorescent probe 3 was synthesized by condensing salicylaldehyde and nicotinic hydrazide for the selective detection of CO₃^2- in aqueous medium. Probe 3 exhibited a turn-on fluorescence response toward CO₃^2- with excellent selectivity, sensitivity (DL = 2.76 μM), and good reversibility. The binding constant (K) of probe 3 with CO₃^2- was calculated to be 5 × 10³ M^-1 (log K 3.69). The 1:1 stoichiometry of the complex between probe 3 and CO₃^2- ions was confirmed by Job's plot and ESI-MS spectra. Deprotonation and hydrogen-bonding interactions are involved in the recognition of CO₃^2- ion, which was also suggested by ¹H NMR, ESI-MS spectra, and Density Functional Theory (DFT) calculations. Moreover, an INHIBIT type molecular logic gate was constructed by using 3:CO₃^2- and CH₃COOH as inputs and current signal as output. Owing to the practical applications, probe 3 demonstrated its efficiency in quantifying CO₃^2- ion in real water samples through standard addition method, thus showcasing its potential in real environment. Further, the MTT assay indicated very low cytotoxicity (IC₅₀ = 1 mM) of probe 3 and also the cell imaging experiments demonstrated the effective sensing of CO₃^2- ions with probe 3 in the biological systems.

Keywords: Carbonate sensor; Chemosensors; Fluorescent sensors; Live cell imaging; Real water testing; Turn on probe.