Pyrene-Armed Calix[4]azacrowns as New Fluorescent Ionophores:  “Molecular Taekowndo” Process via Fluorescence Change

Abstract

A series of new calixarene-based fluoroionophores were synthesized. With our new calixarene derivative bearing a crown ether and an azacrown ether as two binding sites, the metal ion was found to selectively choose its better binding pocket between these two ligands. Interesting "molecular taekowndo" processes between Ag(+)-K(+), Cu(2+)-K(+), and Ag(+)-Cs(+) pairs were easily monitored via fluorescence change.

Metal ion complexation in acetonitrile by upper-rim benzyl-substituted, di-ionized calix[4]arenes bearing two dansyl fluorophores

“…[1][2][3][4][5][6] Various chemosensors based on calix [4]arenes bearing fluorescent groups have been synthesized for investigation of their fluorescent responses upon complexation with metal cations. [7][8][9][10] Several photoinduced mechanisms have been proposed to substituents on the upper and/or lower rims may influence the metal ion complexation process.…”

N-Anthracenylmethyl Calix[4]azacrowns as New Fluorescent Ionophores

“…15 As a continued project on the fluorescent ionophores, we here report the synthesis of Nanthracenylmethyl calixazacrown and corresponding calixbis-azacrowns and their fluorescent changes upon the addition of various metal ions. In this system, the nitrogen moiety of the azacrown ring not only participates in the selective binding, but also serves as a probe for the CHEF effect.…”

“…), we found that 1 (5.0 µM) displayed large chelation-enhanced fluorescence (CHEF) effects with Zn plotting experiment. 15 This is because there is an electrostatic repulsion between the two metal ions in solution and is an induced conformation change that does not favor binding of the second metal ion. 17 From the results of fluorescence changes indicated in Figure 2, one can conclude that 2 is somewhat less sensitive for metal ion binding than 1 in alkali and alkaline-earth metal ion series.…”

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

“…Pyrenes are a particularly elegant basis for ratiometric based optical sensors, where the ratio of two emission wavelengths comprised the analytical signal. To date the pyrene excimer/monomer system has been exploited mainly for cation sensing [5][6][7][8][9][10][11][12][13][14][15][16] and increasingly for anion sensing.…”