An Efficient Fluorescence "Turn-On" Chemosensor Comprising of Coumarin and Rhodamine Moieties for Al and Hg.

A potent fluorescence 'turn-on' receptor (HL) based on rhodamine and coumarin moieties for the detection of Hg and Al is synthesized by condensation of rhodamine 6G hydrazide and 4-hydroxy-3-acetylcoumarin. In presence of Al and/or Hg the receptor (HL) exhibits deep pink colouration and a sharp band at 528 nm is appeared in UV-vis titration. Upon gradual addition of Al and/or Hg to the solution of HL significant enhancement of fluorescence intensity is observed at 564 nm in MeCN:HO (1:5, v/v) medium. The receptor is strongly bound to Al and/or Hg and the association constants (K) are found to be 1.74 × 10 and 1.04 × 10 M for Al and Hg respectively. Graphical Abstract A potent fluorescence 'turn-on' receptor (HL) based on rhodamine and coumarin moieties for the detection of Hg and Al is synthesized and characterized. In presence of Al and/or Hg the receptor (HL) exhibits deep pink colouration and significant enhancement of fluorescence intensity is observed at 564 nm in MeCN:HO (1:5, v/v) medium. The receptor is strongly bound to Al and/or Hg and the association constants (K) are found to be 1.74 × 10 and 1.04 × 10 M for Al and Hg respectively.