Ribose-protected thioguanosine-based 1H NMR spectroscopic probe for the detection of cesium from solid cesium-containing sources in acetonitrile

Ribose-protected thioguanosine (TG) exhibited remarkable preference for cesium over other alkali metal (Na+, K+, Rb+) and alkaline earth metal ions (Mg2+, Ca2+, Sr2+, Ba2+) in acetonitrile by 1H NMR measurements. Furthermore, TG displayed excellent sensitivity for cesium even under 500/1 NaCl/CsCl and KCl/CsCl environments. The most distinct feature is that only in a cesium environment, the thioamide NH peak becomes highly broadened and finally disappeared, and the amino NH2 peak shows a downfield shift, suggesting that TG-based 1H NMR spectroscopic probe is factually useful for the detection of cesium from solid cesium-containing sources in organic solvents.