1,2,4-Triazine-picolinamide functionalized, nonadentate chelates for the segregation of lanthanides(<scp>iii</scp>) and actinides(<scp>iii</scp>) in biphasic systems
作者:Gary L. Guillet、I. F. Dempsey Hyatt、Patrick C. Hillesheim、Khalil A. Abboud、Michael J. Scott
DOI:10.1039/c2nj40586e
日期:——
A novel family of nonadentate ligands based on the (5,6-diphenyl-1,2,4-triazin-3-yl)-picolinamide donor moiety has been synthesized from simple starting materials in high yield and purity. This group of ligands is an addition to the neutral nonadentate group but the first to incorporate 1,2,4-triazine. Their ability to extract a select group of lanthanides from acidic aqueous solution has been correlated to their ability to meet the ideal trigonal tricapped prismatic geometry that is seen by lanthanides and actinides in aqueous solution. The rate of metallation was determined using UV/VIS spectroscopy with pseudo first order conditions and showed similar behaviour to literature examples. Theoretical calculations were used to probe the bonding structure with lanthanides and actinides to predict the potential Ln/An segregating ability of the new ligands.
Influence of the platform in multicoordinate ligands for actinide partitioning
作者:Henk H. Dam、David N. Reinhoudt、Willem Verboom
DOI:10.1039/b704667g
日期:——
Multicoordinate 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 multicoordinate 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 (CTV6PICOSAm/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.