Quinoline Driven Fluorescence Turn On 1,3-Bis-calix[4]arene Conjugate-Based Receptor to Discriminate Fe³⁺ from Fe²⁺

The synthesis and characterization of a triazole linked quinoline appended calix[4]­arene conjugate, L, and its fluorescence turn on receptor property for Fe³⁺ have been demonstrated. The selective and sensitive discrimination of Fe³⁺ has been shown using fluorescence and absorption titration experiments. The Fe³⁺ binding to L has been further shown by ITC and ESI MS. The mode of binding of Fe³⁺ by calix[4]­arene conjugate has been shown by absorption, ¹H NMR and visual color change and the species were modeled based on DFT computations. The {L + Fe³⁺} has been shown to label cells with fluorescence imaging. Moreover the utility of this conjugate has been demonstrated by the combination logic gate system.