Browsing by Author "Balamurugan, Gopal"

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A triple action chemosensor for Cu2+ by chromogenic, Cr3+ by fluorogenic and CN- by relay recognition methods with bio-imaging of HeLa cells
(2017-09-01)
Vijay, Natarajan
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Balamurugan, Gopal
;
Venkatesan, Parthiban
;
Wu, Shu Pao
;
Velmathi, Sivan
A triple action chemosensor (R1) bearing a rhodamine and thiophene moiety was synthesized by a simple condensation reaction. The sensing behaviour and selectivity of the synthesized chemosensor toward metal ions were studied by UV-Vis and fluorescence spectroscopy. The chemosensor recognized Cu2+ and Cr3+ ions with significant changes in UV-Vis absorbance and fluorescence intensity. The results showed that Cr3+ induced greater fluorescence enhancement whereas Cu2+ ions bound strongly with the receptor by showing a strong absorption band at 554 nm but with weak fluorescence. A visible colour change was observed by the addition of Cu2+ and that colour change is due to the opening of the spirolactam ring triggered by the addition of Cu2+ ions. Job's plot analysis indicated a 1 : 2 and 1 : 1 binding stoichiometry between the chemosensor and Cr3+/Cu2+. Subsequently, the R1 - Cu2+ complex chemosensor was employed to detect CN- in the presence of different anions, such as F-, Cl-, Br-, I-, AcO-, H2PO4-, HSO4-, NO3- and -OH. In addition, the live cell imaging of HeLa cells using R1 and Cr3+ was demonstrated successfully.
New phenazine based AIE probes for selective detection of aluminium(III) ions in presence of other trivalent metal ions in living cells
(2017-12-21)
Balamurugan, Gopal
;
Velmathi, Sivan
;
Thirumalaivasan, Natesan
;
Wu, Shu Pao
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應用化學系
Phenazine fluorophore based imidazole derivatives (S1 and S2) were synthesized and sensor studies were carried out with various cations. Aggregation induced emission (AIE) was observed selectively for Al3+ among other cations under study in case of both sensors. H-1 NMR titration supported the aggregation induced emission of S2 with Al3+. ESI mass spectra successfully confirmed the aggregate formation. SEM images clearly showed the aggregation of receptor induced by Al3+ in a flower-like fashion. AIE probe was successfully applied for bio-imaging of RAW264.7 cells.
Novel ratiometric turn-on fluorescent probe for selective sensing of cyanide ions, effect of substitution and bio-imaging studies
(2016-01-01)
Balamurugan, Gopal
;
Venkatesan, Parthiban
;
Wu, Shu Pao
;
Velmathi, Sivan
;
應用化學系
Novel fluorogenic receptors S1-S4 (imidazo anthraquinone derivatives) were synthesized from o-substituted benzaldehyde and 1,2-diaminoanthraquinone and characterised with various spectroanalytical techniques. In the case of S1, the selectivity towards cyanide ions with turn-on fluorescence output among other anions, due to the inhibition of the twisted intramolecular charge transfer (TICT) mechanism. The effect of substitution was successfully compared with sensing studies of S2-S4. S1 showed a good binding constant with a 1 : 1 stoichiometric ratio and micromolar detection limit. The sensing behaviour was further supported by H-1 NMR titration, TD-DFT calculations and lifetime measurement studies. S1 was applied for the bio-imaging of the cell line RAW264.7 and successfully sensed cyanide ions under physiological conditions.