A novel pyrazole bearing imidazole frame as ratiometric fluorescent chemosensor for Al3+/Fe3+ ions and its application in HeLa cell imaging.

New pyrazole bearing imidazole derivative was successfully synthesized and thoroughly characterized by various spectroanalytical techniques. The sensor DIBI shows a highly selective and sensitive fluorescent response with the addition of Al3+/Fe3+ ions in acetonitrile-water mixture. The strong fluorescent molecule exhibits a notable ratiometric emissions at 462 nm and 470 nm for Al3+ and Fe3+ ions, respectively (λex = 280 nm). Job's plot studies conclude that the coordination between DIBI with Al3+/Fe3+ was 1:1 binding stoichiometry. The limit of detection of DIBI with Al3+/Fe3+ was calculated as 2.12 × 10-7 M and 1.73 × 10-6 M, respectively. The TD-DFT calculations further supported the photonics performances of the free probe and its complexes. The reversibility and reusability of the sensor molecule are studied using EDTA. The probe was used to track Al3+/Fe3+ in cancer cells via fluorescence microscopy.

Execution of julolidine based derivative as bifunctional chemosensor for Zn2+ and Cu2+ ions: Applications in bio-imaging and molecular logic gate.

A simple julolidine based chemosensor (JT) was designed and synthesized by single condensation step. JT displayed excellent selectivity and sensitivity with on-off responses towards Zn2+ and Cu2+ over other biologically relevant metal ions in aqueous media. Upon addition of Zn2+ ions, JT exhibited a significant blue shift in emission followed by turn-on enhancement while with Cu2+, the fluorescence intensity of JT was completely vanished. The 1:1 binding affinity between JT and Zn2+/Cu2+ was proposed by Job's plot analysis. The detection limit for Zn2+ and Cu2+ ions reached at 3.5 × 10-8 M and 1.46 × 10-6 M, respectively. The sensing mechanism of JT with Zn2+/Cu2+ was supported by DFT calculations. Based on photophysical studies and its reversibility environment with EDTA, molecular logic gates were fabricated. Furthermore, JT was successfully established to detect intracellular Zn2+ ions in live cells by turn-on response.