Synthesis of biscarbazole derivative, detection of the "on-off" sensor property of Cu by fluorimetry, and anti-cancer evaluation.

Biscarbazole derivative probe (6) (Z)-2-(3-(((9-heptyl-9H-carbazol-3-yl)methylene)amino)-9H-carbazol-9-yl)ethan-1-ol containing an imine group, which is a sensitive and selective fluorescence chemosensor, was designed and synthesized for the effective evaluation of Cu metal ion levels. The synthesized compounds were characterized using H NMR, C NMR, FT-IR, and MALDI-TOF MS (for compound 6) spectroscopic data. The interaction model between probe 6 and Cu was determined by combining fluorescence methods, H NMR titration, Job's plot, and theoretical calculations. For probe 6, the fluorogenic recognition of Cu was investigated by fluorescence spectroscopy, and the optical changes caused by Cu ions were carried out in ACN/HO (50:50) solution at pH 7.0. Fluorescence probe 6 was found to "turn-off" its fluorescence in the presence of paramagnetic Cu ions. Probe 6 was determined to have a rapid response within 40s and showed a fluorescence response to Cu with a low detection limit of 0.16 μM. Additionally, in vitro anticancer activity and cell imaging studies of probe 6 against the prostate cell line (PC-3) were performed.