A new benzil-based chemosensor for colorimetric and fluorometric detection of Cu2+ with high selectivity and sensitivity in living cells

A novel benzil-based probe DBBQ containing two julolidine Schiff base arms was synthesized and demonstrated for its highly selective and sensitive detection of Cu2+ ions in CH3CN: HEPES buffers (3:2, v/v, pH=7.4). Upon the addition of Cu2+ ions, the absorption of the probe exhibited remarkable change in color from yellow to brown, which could be easily observed by the naked eyes. In addition, probe DBBQ displayed highly selective fluorescence quenching signal for Cu2+ ions over a wide range of competitive substances. The fluorescence intensity of DBBQ in CH3CN: HEPES buffer (3:2, v/v, pH=7.4) solution showed a good linear response relationship to Cu2+ ions in the range of 0–2.5 μΜ and low detection limit of 0.41 μM. The binding ratio between DBBQ and Cu2+ ions was determined to be 1:1. Probe DBBQ could be potentially used as a chemosensor for Cu2+ ions in living HepG2 cells.