Pb²⁺On-Off Switchable 1,3-Alternate Calix[4]arene Chemosensor Containing Urea and Pyrene Moieties

Revisiting Fluorescent Calixarenes: From Molecular Sensors to Smart Materials

“…Nam et al reported pyrene-appended fluorescent calixarene probe 37 (Figure ) for the selective detection of Pb 2+ . Probe 37 showed strong excimer emission at 475 nm and weak monomer emission at 375 nm, signifying that the two pyrene units are in close proximity to one another.…”

Fluorescence and Colorimetric Chemosensors for Fluoride-Ion Detection

“…The chemosensor 105 (Figure 42), containing a urea binding site on the lower rim of a 1,3-alternate calix [4]arene structure was synthesized by Nam and co-workers. 116 These workers observed that addition of Pb 2+ ion to a solution of 105 in acetone-CHCl 3 (v/v = 7:3) promotes quenching of the monomer and excimer bands owing to reverse SET from the pyrene units to the urea groups. The quenching is reversed by addition of F − to the Pb 2+ -105 complex.…”

Excimer‐Based On‐Off Bis(pyreneamide) Macrocyclic Chemosensors

“…[ ] Systems were designed with (i) podand, crown ether, or calixarene‐based fragments for cation binding, (ii) covalently linked pyrenes acting as fluorophores and, upon the presence or absence of metal cations, (iii) sufficiently different conformations to modulate the fluorescence . [ ] For instance, Nakamura et al . reported the synthesis of an alkaline and alkaline earth metal cation sensor composed of a non‐cyclic polyether and two terminal pyrenyl units ( Figure , left) .…”