A hydrolytically stable complexant for minor An separation from Ln in process relevant diluents.

The evaluation of bis-1,2,4-triazine complexants containing eight-carbon, alkoxy-functionalized phenyl substituents at the 3,3'-positions for selective minor actinide extraction in simulated high level waste is reported. The complexant retained chemoselective extraction efficiency of actinides over lanthanides while breaking through the nonpolar diluent solubility and hydrolytic stability barriers that limit many BTP complexants. Thus, we report a BTP complexant that is readily soluble in both kerosene and isooctanol without forming precipitates, emulsions, or third phase after contact with nitric acid and extracts 241Am3+ from 154Eu3+. Separations and spectroscopic data are reported herein.

Next-Generation 3,3'-AlkoxyBTPs as Complexants for Minor Actinide Separation from Lanthanides: A Comprehensive Separations, Spectroscopic, and DFT Study.

Progress toward the closure of the nuclear fuel cycle can be achieved if satisfactory separation strategies for the chemoselective speciation of the trivalent actinides from the lanthanides are realized in a nonproliferative manner. Since Kolarik's initial report on the utility of bis-1,2,4-triazinyl-2,6-pyridines (BTPs) in 1999, a perfect complexant-based, liquid-liquid separation system has yet to be realized. In this report, a comprehensive performance assessment for the separation of 241Am3+ from 154Eu3+ as a model system for spent nuclear fuel using hydrocarbon-actuated alkoxy-BTP complexants is described. These newly discovered complexants realize gains that contemporary aryl-substituted BTPs have yet to achieve, specifically: long-term stability in highly concentrated nitric acid solutions relevant to the low pH of unprocessed spent nuclear fuel, high DAm over DEu in the economical, nonpolar diluent Exxal-8, and the demonstrated capacity to complete the separation cycle with high efficiency by depositing the chelated An3+ to the aqueous layer via decomplexation of the metal-ligand complex. These soft-N-donor BTPs are hypothesized to function as bipolar complexants, effectively traversing the organic/aqueous interface for effective chelation and bound metal/ligand complex solubility. Complexant design, separation assays, spectroscopic analysis, single-crystal X-ray crystallographic data, and DFT calculations are reported.

Synthesis of Tridentate [1,2,4] Triazinyl-Pyridin-2-yl Indole Lewis Basic Complexants via Pd-Catalyzed Suzuki-Miyaura Cross-Coupling.

Full closure of the nuclear fuel cycle is predicated, in part, on defining efficient separations processes for the effective speciation of the neutron-absorbing lanthanides from the minor actinides post-PUREX. Pursuant to the aforementioned, a class of tridentate, Lewis basic procomplexants have been prepared leveraging a Pd-catalyzed Suzuki-Miyaura cross-coupling between 6-bromo-[1,2,4]-triazinylpyridine derivatives and various protected indole-boronic acids to afford functionalized 2-[6-(5,6-diphenyl-[1,2,4]triazin-3-yl)-pyridin-2-yl]-1H-indoles. A highly active catalyst/ligand system with low loadings was employed rapidly affording 26 examples in yields as high as 85%. Method optimization, substrate and indole scope, comparative analysis between coupling reagents, and a scale-up experiment are reported.