The new fluorescence probe based on [5]helicene derivative bearing hydrazine (1) was prepared and fully characterized by NMR, single crystal X-ray analysis and HRMS spectrometry. 1 exhibited highly sensitive detection to Cu2+ through Turn-ON fluorescence with a very large Stokes shift of ~183 nm. 1 also had great selectivity to bind with Cu2+ over other metal ions such as Hg2+, Ag+, Pb2+, Zn2+, Ni2+, Cd2+, K+, Li+, Ba2+, Al3+, Fe2+, Co2+, Mn2+, Ca2+, Na+, and Mg2+ in aqueous acetonitrile solution. Using Job’s plot analysis, it was found that 1 bound with Cu2+ with 1:1 ratio. The optimized structure of 1-Cu2+ at B3LYP/6-311G** level illustrated that Cu2+ coordinated to carbonyl oxygen of helicene and nitrogen from hydrazine moiety with the distances of 2.11 Å and 2.02 Å, respectively. The detection limit of 1 for Cu2+ determination was estimated to be 2.6 ppb which was lower than drinking water permission concentrations by US EPA and WHO. In addition, 1 could be used to monitor Cu2+ in the intracellular area of the HepG2 cellular system. Thus, 1 had potential for Cu2+ detection in biological samples.

Super large Stokes shift and “turn-on” fluorescent probe for Cu2+ detection

256th National Meeting (2018)

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