Differentially Selective Chemosensor with Fluorescence Off-On Responses on Cu2+ and Zn2+ Ions in Aqueous Media and Applications in Pyrophosphate Sensing, Live Cell Imaging, and Cytotoxicity (original) (raw)

2014, Inorganic Chemistry

A new benzoyl hydrazone based chemosensor R is synthesized by Schiff base condensation of 2,6-diformyl-4methylphenol and phenyl carbohydrazide and acts as a highly selective fluorescence sensor for Cu 2+ and Zn 2+ ions in aqueous media. The reaction of R with CuCl 2 or ZnCl 2 forms the corresponding dimeric dicopper(II) [Cu 2 (R)(CH 3 O)-(NO 3 )] 2 (CH 3 O) 2 (R-Cu 2+ ) and dizinc(II) [Zn 2 (R) 2 ](NO 3 ) 2 (R-Zn 2+ ) complexes, which are characterized, as R, by conventional techniques including single-crystal X-ray analysis. Electronic absorption and fluorescence titration studies of R with different metal cations in a CH 3 CN/0.02 M HEPES buffer medium (pH = 7.3) show a highly selective binding affinity only toward Cu 2+ and Zn 2+ ions even in the presence of other commonly coexisting ions such as Na + , K + , Mg 2+ , Ca 2+ , Mn 2+ , Fe 2+ , Fe 3+ , Co 2+ , Ni 2+ , Cd 2+ , and Hg 2+ . Quantification of the fluorescence titration analysis shows that the chemosensor R can indicate the presence of Cu 2+ and Zn 2+ even at very low concentrations of 17.3 and 16.5 ppb, respectively. R-Zn 2+ acts as a selective metal-based fluorescent sensor for inorganic pyrophosphate ion PPi) even in the presence of other common anions such as F − , Cl − , Br − , I − , CH 3 COO − , CO 3 2− , HCO 3 − , N 3 − , SO 4 2−