Fluorophore inserted bisbenzimidazole clefts in selective sensing of Ag+ and Cu2+ ions

- Anthracene and naphthalene tied bisbenzimidazoles 1 and 2 are synthesized.
- The bisbenzimidazole cleft 1 is selective to Ag+ ions in DMSO-H2O (2:1, v/v).
- The bisbenzimidazole cleft 2 is selective to Cu2+ ions in DMSO-H2O (2:1, v/v).
- Turn-off emission with distinguishable color changes under UV is observed.

Anthracene and naphthalene tied bisbenzimidazoles 1 and 2 have been designed and synthesized. The conformational behaviour of the molecules has been rationalized by DFT calculations. While the bisbenzimidazole 1 shows selective sensing of Ag+ ions, under similar conditions the bisbenzimidazole 2 senses Cu2+ in DMSO-H2O (2:1, v/v) by exhibiting turn-off emission. During metal ligand interaction the colors of the receptor solutions are significantly changed under UV-light and are promisingly useful in naked eye detection. Interaction features have been explained by spectroscopic techniques.

Anthracene and naphthalene tied bisbenzimidazoles 1 and 2 have been designed and synthesized. While compound 1 shows selective sensing of Ag+ ions, compound 2 under similar conditions senses Cu2+ in DMSO-H2O (2:1, v/v) by exhibiting turn-off emission and distinguishable color change of probe solutions under UV light.185