ABSTRACT

Fluorescence spectroscopy and time-resolved study have successfully explored the impact of supramolecular assembly, cucurbit[6]uril (CB6) on the dynamics of proton transfer in 2-(4’-pyridyl) benzimidazole (4-PBI). It has been observed that the guest molecules are capable of binding in three different states of protonation: cation C, tautomer T, and neutral N. While the acid–base equilibria is altered by the host molecule in the ground and excited states. Binding modes of the dye molecule with cucurbit[6]uril have been investigated by proton NMR spectroscopy. The binding of the guest with the supramolecular host is further confirmed by Quantum chemical calculations. The current study successfully recognises how the convoluted acid–base equilibria of dye molecule (4-PBI) are affected by cucurbit[6]uril (CB6) supramolecular assembly upon complexation.