Theoretical Study of the Uranyl Complexation by Hydroxamic and Carboxylic Acid Groups
- 23 July 2008
- journal article
- research article
- Published by American Chemical Society (ACS) in Inorganic Chemistry
- Vol. 47 (18), 7983-7991
- https://doi.org/10.1021/ic7018633
Abstract
A theoretical study on the complexation of uranyl cation (UO2(2+)) by three different functional groups of a calix[6]arene cage, that is, two hydroxamic and a carboxylic acid function, has been carried out using density functional theory calculations. In particular, interaction energies between the uranyl and the functional groups have been used to determine their affinity toward uranyl, whereas pKa calculations give some information on the availability of the functional groups in the extraction conditions. On the one hand, calculations of the interaction energies have pointed out clearly a better affinity with the hydroxamic groups. The stabilization of this complex was rationalized in terms of a stronger electrostatic interaction between the uranyl cation and the hydroxamic groups. The presence of a water molecule in the first coordination sphere of uranyl does not destabilize the complex, and the most stable complex is obtained with two functional groups and two water molecules, leading to a coordination number of 8 for the central uranium atom. On the other hand, pKa theoretical evaluation shows that both hydroxamic (deprotonated on the oxygen site) and carboxylic groups are potential extractants in aqueous medium with a preference for carboxylic functions at low pH. Moreover, these data allowed to unambiguously identify the oxygen of the alcohol function as the favored deprotonation site on the hydroxamic function.This publication has 86 references indexed in Scilit:
- Gas-Phase Chemistry of Actinides Ions: New Insights into the Reaction of UO+and UO2+with WaterJournal of the American Chemical Society, 2007
- Ion imprinted polymer based sensor for monitoring toxic uranium in environmental samplesAnalytica Chimica Acta, 2007
- Supramolecular polymeric complexes of calix[8]arenesRussian Journal of Applied Chemistry, 2006
- Theoretical Investigations of Uranyl−Ligand Bonding: Four- and Five-Coordinate Uranyl Cyanide, Isocyanide, Carbonyl, and Hydroxide ComplexesInorganic Chemistry, 2005
- Extraction of uranyl ions from aqueous solutions using silica-gel-bound macrocycles for alpha contaminated waste water treatmentAnalytica Chimica Acta, 2004
- Uranyl Ion Sensing by a Self-Assembled Calix[6]arene MonolayerMolecular Crystals and Liquid Crystals, 2002
- Crystal Structure of the Uranyl Ion Complex of p-tert-Butylcalix[7]areneSupramolecular Chemistry, 1998
- Investigation of U(VI) extraction with calixarene: Application to analysis of urine sampleJournal of Radioanalytical and Nuclear Chemistry, 1997
- Separation and determination of uranium(VI) with calixarene hydroxamic acidsJournal of Radioanalytical and Nuclear Chemistry, 1995
- Selective extraction and transport of UO2 2+ with calixarene-based uranophilesJournal of the Chemical Society, Perkin Transactions 2, 1989