Synthesis and cation binding properties of fluorescent calix[4]arene derivatives bearing tryptophan units at the lower rim (CROSBI ID 165549)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Galić, Nives ; Burić, Nataša ; Tomaš, Renato ; Frkanec, Leo ; Tomišić, Vladislav
engleski
Synthesis and cation binding properties of fluorescent calix[4]arene derivatives bearing tryptophan units at the lower rim
The fluorescent peptidocalixarenes, 5, 11, 17, 23-tetra-tert-butyl-25, 26, 27, 28-tetrakis(O-methyl-L-tryptophanylcarbonylmethoxy)calix[4]arene (1) and 5, 11, 17, 23-tetra-tert-butyl-25, 27-di(O-methyl)-26, 28-bis(O-methyl-L-tryptophanylcarbonylmethoxy)calix[4]arene (2), were prepared by introducing tryptophan subunits at a lower calixarene rim. Coordination abilities of 1 and 2 towards europium(III) and alkali metal cations were studied by spectrophotometric, spectrofluorimetric, conductometric and potentiometric titrations in acetonitrile at 25 oC. Rather strong complexation was observed for smaller alkali metal cations Li+ and Na+ (log KLi1 > 6, log KLi2 > 6, log KNa1 = 8.25, logKNa2 = 6.94), and moderate for K+ (log KK1 = 5.09, log KK2 = 4.09). Larger Rb+ and Cs+ cations did not fit in the ion-binding site of 1 so no complexation was detected, whereas the more flexible ligand 2 accommodated Rb+ cation (log KRb2 = 3.44). The fluorescence of 1 (ex = 280 nm, em = 340 nm) was remarkably quenched by Eu(III). Stability constant of 1:1 (Eu3+:1) complex determined spectrofluorimetrically amounted to log KEu1 = 6.16.
calixarenes ; alkali metal cations ; europium(III) ; stability constants ; fluorescence
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Podaci o izdanju
23 (5)
2011.
389-397
objavljeno
1061-0278
1029-0478
10.1080/10610278.2010.521832