CMPO-Functionalized C₃-Symmetric Tripodal Ligands in Liquid/Liquid Extractions:  Efficient, Selective Recognition of Pu(IV) with Low Affinity for 3+ Metal Ions

Abstract

Structural modifications of carbamoylmethylphosphine oxide (CPMO)-functionalized triphenoxymethane platforms are described, and the influence of these changes on the ability of the ligand to extract actinides from simulated acidic nuclear waste streams has been evaluated. The ligand system has been shown to have excellent binding efficiency and a selectivity for An(IV) in comparison to the a simple monomeric CMPO ligand under analogous conditions. Both the extraction efficiency and selectivity are strongly dependent on the flexibility and electronic properties of the ligating units in the triphenoxymethane construct. The Tb(III) and Bi(III) nitrate complexes of tris-CMPO derivatives have been isolated, and their structures were elucidated by NMR, ESI FT-ICR MS, and X-ray analysis, providing information on the interactions between metal ions and the tris-CMPO molecules.

1,2,4-Triazine-picolinamide functionalized, nonadentate chelates for the segregation of lanthanides(iii) and actinides(iii) in biphasic systems

“…1). [39][40][41][42][43] Additionally, the triphenoxymethane scaffold allows facile synthetic modulation of the alkyl substitution on the platform by choice of 2,4-substituted phenol.…”

The actinides

“…56 Binding the carbamoylmethylphosphine oxide ligand to a triphenoxymethane platform considerably enhances its ability to extract Pu 4+ from aqueous solution. 57 Pu(IV) complexation by the natural siderophore Desferrioxamine B has been examined; Pu(III) complexes of these ligands are at least 20 orders of magnitude less stable, so that stable Pu(siderophore) complexes are unlikely under reducing conditions. 58 Citrate forms complexes M(cit) and [M(cit) 2 ] 3À with Am 3+ , Cm 3+ and Eu 3+ ; the ternary complexes [M(EDTA)(Cit)] 4À (M = Cm and Eu) have large stability constants (log b 111 4 20).…”

Steric hindrance effects in tripodal ligands for extraction and back-extraction of Ag+

“…In particular, tripodal ligands have been used as extractants for metals. [6][7][8][9][10] From an economic and environmental standpoint, it is of great importance to recover expensive metals for reuse and recycling from electronic waste, or to remove metal contaminants from wastewater. [11][12][13][14][15] Examples include heavy metals, radioactive precious metals, rare metals, and rare earth metals.…”