Browsing by Author "Prakash, Epperla Chandra"

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A facile ratiometric fluorescent chemodosimeter for hydrazine based on Ing-Manske hydrazinolysis and its applications in living cells
(2014-04-01)
Raju, Mandapati V. Ramakrishnam
;
Prakash, Epperla Chandra
;
Chang, Huan-Cheng
;
Lin, Hong-Cheu
;
材料科學與工程學系
A facile and sensitive fluorescent probe for hydrazine was successfully constructed, displaying excellent colorimetric and ratiometric responses towards hydrazine via Ing-Manske hydrazinolysis conditions in semi-aqueous buffer solution. Semi-empirical calculations as well as spectroscopic results revealed the signalling mechanism of the current probe under hydrazinolysis conditions, in which hydrazine exclusively deprotected the phthalimide group by an intermediate of phthalhydrazide. Extensive screening of pH effects on the probe with the aid of proton nuclear magnetic resonance and mass spectrometry supported the distinctive and diverse ratiometric responses under hydrazinolysis and basic hydrolysis conditions. Time resolved photoluminescence measurements of the probe further confirmed its discernible ratiometric responses probed at respective wavelengths. A distinctive ratiometric response under basic hydrolysis conditions and a successful utilization of probe towards hydrazine detection in living cells are demonstrated. (C) 2013 Elsevier Ltd. All rights reserved.
A new pyrene-based aggregation induced ratiometric emission probe for selective detections of trivalent metal ions and its living cell application
(2015-02-01)
Singh, Ashutosh
;
Singh, Ravinder
;
Shellaiah, Muthaiah
;
Prakash, Epperla Chandra
;
Chang, Huan-Cheng
We synthesize a newly designed pyrene-based fluorescent probe FBP containing a Schiff base and amide linkage as a receptor, which demonstrates selective UV-vis and fluorometric detections of trivalent metal ions in various semi-aqueous solution conditions. Interestingly, by increasing water contents the aggregation induced ratiometric emissions (AIREs) of photoluminescence in FBP solutions (in DMSO/H2O) are enhanced from blue to green due to the excimer formation of the aggregates in water. In addition, the enhanced aggregated ratiometric green fluorescence behaviors of FBP in the presence of trivalent metal ions (Al3+, Fe3+, and Cr3+) are observed in semi-aqueous solutions as well as the solid state, which is well utilized to detect trivalent metal ions in living cells. Further verification of the probe detections, their interactions toward trivalent metal ions are well characterized by the time-resolved photoluminescence (TRPL) of spectroscopic responses as well as theoretical calculations. Therefore, we believe the application of such a new AIRE-based approach is first reported among Schiff base and pyrene-based fluorescentchemo- and bio-sensors. (C) 2014 Elsevier B.V. All rights reserved.