Ultrafast and selective separation of Tc from molybdenum matrix using DBDGA deliberately tailored macrocyclic crown-ethers.

Technetium-99m (Tc) is an important medical radionuclide. Due to the crisis in supply of molybdenum-99 (Mo), production of Tc directly via the Mo (p, 2 n) reaction by cyclotron was proposed. In this process, the most critical challenge is to rapidly and efficiently separate Tc from high concentration of molybdenum. In this work, a novel ligand, bis(N,N-dibutyldiglycolamide)dibenzo-18-crown-6 (BisDBDGA-DB18C6) was successfully synthesized and used for extraction of TcO /ReO from molybdenum. The results demonstrated that BisDBDGA-DB18C6 expressed excellent selectivity for TcO with a high separation factor of 1.6 × 10 against Mo, a fast extraction kinetic (within 45 s), and a high extraction capacity of 211 mmol ReO (TcO)/per mole of extractant. The extraction mechanism was proposed as a co-interaction of macrocyclic crown ether and N,N-dibutyldiglycolamide group through slope analysis, FT-IR, ESI-MS, H NMR titration and theory calculations. Importantly, Tc in the organic phase can be quantitatively (> 99%) and easily back-extracted using deionized water, which can be directly used for medical applications.