A through bond energy transfer based ratiometric probe for fluorescent imaging of Sn2+ ions in living cells

A 4-(naphthalen-1-ylethynyl) aniline appended rhodamine based fluorescent chemosensor 'NAP-RD' is synthesized which undergoes through bond energy transfer in the presence of Sn2+ ions in mixed aqueous media. NAP-RD is an excellent colorimetric and fluorescence ratiometric probe which recognizes traces of Sn2+ in real samples and a fluorescence indicator in living RAW264.7 cells. The new sensing probe NAP-RD shows higher sensitivity as well as faster response compared to the reported systems. The detection limit of NAP-RD is 5 x 10(-9) M. DFT studies strongly support the experimental results.