Figure 1.

¹⁹F-NMR of fluorinated chelates designed for Zn²⁺ binding studies. (a) The chemical structure of the synthesized fluorinated chelates 1, 2, and 3 with the fluorine substituent at the 6, 3, and 5 positions of the pyridine ring, respectively. (b) Schematic illustration of the dynamic exchange process between the free and Zn²⁺-bound chelate and the obtained ¹⁹F-NMR spectrum of 1, 2, and 3 in the presence of Zn²⁺ at 25 °C (3 mM chelate and 0.6 mM ZnCl₂ at 100 mM Hepes buffer, pH = 7.2, 9.4 T NMR). Shown are the chemical shift offsets (Δω) between the peak of the free chelate (set at 0.0 ppm) and the peak Zn²⁺-chelate complex.