Influence of the platform in multi coordinate ligands for actinide partitioning

Multi-coordinate ligands based on the trityl, C-pivot, and CTV platforms and the ligating groups CMPO, DGA, PICO, and MPMA were synthesized and studied for their extraction properties. The extraction efficiencies of these multi-coordinate ligands are largely influenced by the properties of the platform. The DAm values follow the order CTV6 ≥ trityl ∼ C-pivot ≥> CTV3 ≥ CTV0 with a maximum for CTV6CMPO of DAm = 30 (SAm/Eu 1.4, cL= 10-4 M, 3 M HNO3). There is a strong relationship between the DAm values, increasing in the order of CTV0CMPO ≤ CTV3CMPO ≤ CTV6CMPO, and the mobility of their CMPO groups. The SAm/Eu values are less influenced by the platform and range between 0.2 and 2.0, though they can reverse under the influence of the HNO3 concentration (CTV6PICO SAm/Eu 0.7 at 0.001 M HNO3 to 1.2 at 0.01 M HNO3) or by changing the platform (CTV(0, 3 or 6)MPMA from SAm/Eu = 0.4 to 1.6 for tritMPMA both at 0.001 M HNO3). For the CMPO derivatives the SAm/Eu values are most consistent, ranging from 1.4 to 1.8. (authors)