Thiadiazole Functionalized Salicylaldehyde-Schiff Base as a pH-responsive and chemo-reversible 'Turn-Off' fluorescent probe for selective cu (II) detection: Logic Gate Behaviour and Molecular Docking Studies

Autor: Aruna Chhikara, Deepak Tomar, Gaurav Bartwal, Madhuri Chaurasia, Anuj Sharma, Swarita Gopal, Sulekh Chandra
Rok vydání: 2022
Předmět:
Zdroj: Journal of Fluorescence. 33:25-41
ISSN: 1573-4994
1053-0509
DOI: 10.1007/s10895-022-02991-6
Popis: A novel thiadiazole functionalized schiff base chemoreceptor (E)-2,4-dichloro-6-(((5-mercapto-1,3,4-thiadiazol-2-yl)imino)methyl)phenol (SB-1) has been synthesized and characterized spectroscopically by using various techniques. Its photophysical behaviour was scanned towards a variety of metal ions in mixed aqueous media. The chemosensor (SB-1) displayed excellent selectivity towards Cu2+ ion through fluorescent diminishment (turn-off phenomenon). Colorimetric analyses showed a rapid colour change from yellow to dark red under visible light upon addition of Cu2+ ions. Interestingly, the original yellow colour reappeared back instantly after the addition of EDTA2- anions, thus confirming the reversible nature of SB-1. Competitive experiments validated no interference from the other co-existing metal ions in the recognition process of SB-1 towards Cu2+ ion. Job’s plot confirmed 1:1 binding stoichiometry between SB-1 and Cu2+ ion with the binding constant value of 3.87×104 M-1. The limit of detection was determined to be 1.01×10-7 M suggesting good sensitivity of SB-1 towards Cu2+ ions. Furthermore, pH-dependent UV-Vis spectral behaviour of SB-1 confirmed that it could act as an effective optical pH-sensor for highly acidic environment as well. Portable nature of probe SB-1 was explored by fabricating “easy-to-use” paper test strips, which allow robust and rapid detection of Cu2+ ions. Based on the multi-responsive properties of SB-1, a ‘NOR’ logic gate was constructed by applying Cu2+ and EDTA2- as chemical inputs (ln1: Cu2+, ln2: EDTA2-) while emission intensity observed at 560 nm was considered as output signal (O1). DFT optimized geometries confirmed that chemosensor SB-1 exists in Azo form (Enol form) in its ground state. Molecular docking of the SB-1 and its copper complex, into the binding site of TRK protein tyrosine kinase (PDB: 1t46) was also carried out to explore their biological activity and their potential use as TRK inhibitors.
Databáze: OpenAIRE
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