Uranium, chelates

Fontaine, R., Santoni, B., Prommier, C., Guiochon, G. Preparation and gas chromatographic analysis of thorium and uranium chelates. Chromatographia 3, 532 (1970). 

Heteroleptic complexes of uranium can be stabilized by the presence of the ancillary ligands however, the chemistry is dominated by methyl and benzyl ligands. Examples of these materials include UR4(dmpe) (R = alkyl, benzyl) and U(benzyl)4MgCl2. The former compounds coordinate "soft" chelating phosphine ligands, a rarity for the hard U(IV) atom. 

Higher phytoextraction coefficients indicate higher metal uptake. The effectiveness of phytoextraction can be limited by the sorption of metals to soil particles and the low solubility of the metals however, metals can be solubilized through the addition of acids or chelating agents and so allow uptake of the contaminant by the plant. Ethylene diamine tetra-acetic acid (EDTA), citric acid, and ammonium nitrate have been reported to help in the solubilization of lead, uranium, and cesium... 

Egawa, H., Nonaka, T., Ikari, M., preparation of macroreticular chelating resins containing dihydroxyphosphino and/or phosphono groups and their adsorption ability for uranium. J. Appl. Polym. Sci. 29, 1984,2045-2055. 

Although not part of soil, lichens, by virtue of their solubilising action on rocks, contribute to the elemental enrichment of soil. Several studies have identified lichen acids as complexing agents for the iron and aluminium of rocks (95, 96). An examination of the various structures indicates that the basic structure responsible for the chelation is the carboxylic acid group with an orthophenolic group. Grodzinskii (97) has found lichens to be intense accumulators of elements in the uranium-radium, actinouranium and thorium orders. 

Premuzic ET, Francis AJ, Lin M, et al. 1985. Induced formation of chelating agents by Pseudomonas aeruginosa grown in presence of thorium and uranium. Arch Environ Contam Toxicol 14 759- 768. 

Young WN, Tebrock HA. 1958. The treatment of exposure to thorium and uranium with a chelating agent and supportive measures. Ind Med Surg (Annual Meeting) 27 229-232. 

Martin, DF Alldredge R. Removal of Uranium(VI) from Water Samples Using Octo-lig and Ferrilig, an Iron Derivative of Octolig, a Supported Chelating Agent. Florida Scientist 2008 71 208-214. 

Five crystal modifications of anhydrous U02(MeC02)2 have been reported. The structure of the dihydrate consists of chains of pentagonal bipyramidal coordination polyhedra in which half of the MeC02 groups link adjacent bipyramids and the remainder are chelated to individual uranium atoms one water molecule is bonded to each uranium atom.2783... 

New chelating polymers having high adsorption ability for uranium have been given much attention with respect to recovery and purification of uranium. The polymers having hydroxamic acid (24), amidoxime (25), dihydroxyphospino, or... 

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