Benzimidazolium-based receptors: Case of iodide–water cluster induced supramolecular chain and improved fluorometric binding of iodide involving alcoholic group

• Benzimidazolium-based receptor for iodide binding.
• Iodide–water cluster.
• Involvement of alcoholic group.
• Fluorometric sensing of iodide.
• Hydrogen bonding and charge–charge interaction.

Benzimidazolium-based receptors 1 and 2 have been designed and synthesized. Anion binding studies reveal their selective fluorescence sensing of iodide in the excited state by exhibiting greater quenching of emission of anthracene. In the ground state, they prefer to bind bromide ion. Incorporation of alcoholic –OH in 2 leads to better performance over the receptor 1. The cyclooctameric structure as constituted by inclusion water and iodide interaction leads to ID-supramolecular chain with the structure 1 in the solid state. 1H NMR, UV–vis and fluorescence spectroscopic methods were adopted to study the anion binding behavior.