4-Methyl-2, 6-diformylphenol based biocompatible chemosensors for pH: discrimination between normal cells and cancer cells. Issue 26 (20th April 2020)

• Record Type: Journal Article
• Authors: Dhawa, Tanumoy; Hazra, Ananta; Barma, Arpita; Pal, Kunal; Karmakar, Parimal; Roy, Partha
• Is Part Of: RSC advances. Volume 10:Issue 26(2020)
• Page Start: 15501
• Page End: 15513
• Publication Date: 2020-04-20
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0ra00754d
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Two 4-methyl-2, 6-diformylphenol based compounds with pyridylamine have been established as chemosensors for pH. The probes are able to differentiate between normal cells and cancer cells. Abstract : Two compounds, namely, 2-hydroxy-5-methyl-3-((pyridin-2-ylimino)methyl)benzaldehyde (HM-2py-B ) and 2-hydroxy-5-methyl-3-((pyridin-3-ylimino)methyl)benzaldehyde (HM-3py-B ), have been explored as fluorescent chemosensors for pH. HM-2py-B and HM-3py-B were synthesized by single step condensation reaction between 4-methyl-2, 6-diformylphenol and the appropriate aminopyridine. These compounds have been characterized by elemental analysis, FT-IR, 1 H NMR, 13 C NMR, ESI mass spectrometry, and absorption and fluorescence spectroscopy. Their structures have been confirmed by single crystal X-ray diffraction analysis. Both of the compounds show low emission at 530 nm at low pH. Fluorescence intensity increases with the increase in pH. With the alteration in pH of the medium from 4.0 to 10.0, the fluorescence intensity at 530 nm enhances by 66 and 195 fold for HM-2py-B and HM-3py-B, respectively. p K a values of HM-2py-B and HM-3py-B have been determined to be 7.15 and 6.57, respectively. Fluorescence increase occurs mainly due to deprotonation of the phenolic OH group. Several cations and anions could not induce significant change in fluorescence behavior for both of the probes. The quantum yield and life-time enhance significantly when the pH of the medium is changed from 5.0 to 9.0. Naked eye identification of different pH environments is possible by using these compounds. Some theoretical calculations have been carried out to support experimentally obtained spectral transitions. As cancer cell has a pH in the range of 5.5–7.0 in comparison to normal cell pH of 7.4, these probes have been used effectively to discriminate between normal cells and cancer cells.