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A new coumarin based fluorescent switch PCEH is fabricated which displays high selective sensing towards Al3+ among other metal cations at physiological pH. On gradual addition of Al3+, PCEH shows a brilliant "turn-on" emission enhancement in MeOH/H2O (4/1, v/v) solution. This new fluorescent switch is proven to be a reversible probe by gradual addition of F− into the PCEH-Al3+ solution. Detection limit as well as binding constant values are calculated to be in the order of 10–9 M and 104 M−1 respectively. We have also explored its potential as a biomarker in the application of live cell imaging using breast cancer cells (MDA-MB-231 cell). [ABSTRACT FROM AUTHOR]

A novel coumarin based azo-phenol ligand (H 2 L) has been synthesized and characterized by several spectroscopic techniques. An almost 16 fold enhancement of emission intensity has been observed upon gradual addition of Mg 2+ to H 2 L in DMSO:H 2 O (1:5 v/v) medium while it has no significant effect in emission intensity even in presence of other metal ions. The emission intensity of L-Mg 2+ complex has almost quenched on gradual addition of F − to it. The limit of detection for both Mg 2+ and F − are of 10 −8 M order, hence the newly developed chemosensor is highly efficient in detecting Mg 2+ and F − in very minute levels. The chemosensor can even detect Mg 2+ in the intracellular region of human lung cancer cells (A549 cells). [ABSTRACT FROM AUTHOR]

• Herein, we report the synthesis and cation sensing properties of a new fluorescence reversible "turn-on" probe (HCBP). • HCBP selectively detects Al3+ in aqueous methanol medium at physiological pH with the enhancement of emission intensity. • Limit of detection (LOD) of the probe towards Al3+ is found to be in the order of 10-9 M. • Electronic structure and sensing mechanism of the probe is interpreted by DFT calculations. • The fluorescence imaging is performed using gastric cancer cells (AGS). A new coumarin based fluorescent switch (HCBP) has been fabricated which displays high selective sensing towards Al3+ among other metal cations at physiological pH. On gradual addition of Al3+ specifically, HCBP shows a brilliant "turn-on" emission enhancement of about ∼13-fold with about 50 nm red shift at 481 nm in MeOH/H 2 O (1/1, v/v) solution. The fluorescent switch is proven to be a reversible probe by addition of EDTA gradually into the HCBP-Al3+ solution. Detection limit as well as Binding constant values have been calculated and found to be in the order of 10−9 M and 103 M-1 respectively. DFT and TDDFT studies are conducted with the probe to establish a similarity between theoretical and experimental outcomes. We can also use this new fluorescent switch as a biomarker kit as it has shown a brilliant potential in the application of live cell imaging using gastric cancer cell (AGS cell). [ABSTRACT FROM AUTHOR]

A highly sensitive and selective coumarin based chemosensor H 2 L for the efficient detection of Al 3+ has been developed. The synthesized chemosensor H 2 L is efficient in detecting Al 3+ over other metal ions which are commonly obtained in various physiological and environmental samples. H 2 L shows fluorescence ‘turn-on’ response at 610 nm in presence of Al 3+ , without the interference of other metal ions. The resulting H 2 L-Al 3+ complex behave as a sequential chemosensor for F − , by showing quenching of emission intensity upon addition of F − to it. This quenching of emission intensity is only specific for F − and is not hampered due to the presence of other anions that commonly coexist with F − in various environmental solutions. Theoretical calculations using DFT/B3LYP method has been used to get insight into the sensing mechanism as well as electronic structure of the synthesized chemosensor H 2 L. H 2 L is efficient in detecting Al 3+ in the intracellular region of human A549 cell and also exhibits an INHIBIT logic gate with Al 3+ and F − as chemical inputs by monitoring the emission mode at 610 nm. [ABSTRACT FROM AUTHOR]