Selective complexation of UO 2 2+ by the calix[6]arene6? anion: Structure and hydration studied by molecular dynamics simulations

Guilbaud, Philippe; Wipff, Georges

doi:10.1007/bf00709150

Cited by 36 publications

(30 citation statements)

References 48 publications

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“…The reaction between UC1, (0.5 mmolej and p-tert-butylcalix [6]arene (0.25 mmole) in presence of triethylamine (5 ml) was carried out in non properly dehydrated and deoxygenated acetonitrile (15 mlj as a solvent, which resulted in an hydrolysis and oxydation of UCl, leading to UO;' and HCI. A dark brown solution resulted, which was filtered and concentrated under vacuum.…”

Section: Synthesismentioning

confidence: 99%

“…Short contacts, which suggest the formation of hydrogen bonds, exist between the hydronium ions and two phenolic oxygen atoms non-bonded to the uranyl ion ( 0 2 and 05) and with the nitrogen atom of one acetonitrile molecule (N3) which is included in the hydrophobic cavity of the calixarene. The inclusion of two acetonitrile molecules in free p-tert-butylcalix [6] arene has previously been described": in both cases, the acetonitrile molecules are out of the pseudo-twofold axis perpendicular to the oxygen atoms mean plane, and tilted with respect to it. Regarding the calixarene moiety itself, This complex provides an example of a rather unusual structure: such a dimerization of two macromolecular units by uranyl ions, which gives rise to a "globular" calixarene dimer encompassing the coordinated metal ions, has not been described previously.…”

mentioning

confidence: 98%

“…Recently, we have described the structure of two phases of a bimetallic complex of uranyl with p-ferr-butylcalix [8] arene3.4, in which the two uranyl ions are bonded to four calixarene oxygen atoms (two protonated and two deprotonated) and one bridging hydroxyl ion. Molecular modeling calculations suggest the possibility of including the uranyl ion in the calix [5]-and calix [6]arene cavities6, but the structures of such complexes have not yet been described. We report here the structure of a dimeric uranyl/p-tert-butylcalix[6]arene complex.…”

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confidence: 99%

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Crystal structure of an uranyl/p-tert-butyl calix[6]arene dimer

Thuéry

Lance

Nierlich

1996

Supramolecular Chemistry

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Section: Synthesismentioning

confidence: 99%

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confidence: 98%

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confidence: 99%

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Crystal structure of an uranyl/p-tert-butyl calix[6]arene dimer

Thuéry

Lance

Nierlich

1996

Supramolecular Chemistry

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“…Molecular mechanics studies of complexes of UO 2 2+ and the calix-6-arene ligands in aqueous solution have observed that the ligand deforms sufficiently such that only five of the six oxygens on the ligand bind to the cation, thus giving a uranium coordination of z ) 7. 8 The observation of the uranyl and 18C6 complex in aqueous solution again suggests that the uranium * Author to whom correspondence should be addressed. Fax: +44 (0)-1223 336535.…”

Section: Introductionmentioning

confidence: 96%

Hydration of UO₂²⁺ and PuO₂²⁺

et al. 1999

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We study the hydration of the actinyl cations, uranyl UO 2 2+ and plutonyl PuO 2 2+ , by performing KohnSham Density Functional Theory calculations using a new quantum chemistry codesMAGIC. The calculations have been performed on the separate uranyl and plutonyl species, and on the complexes AcO 2 2+ ‚nH 2 O (Ac ) U, Pu and n ) 4, 5, and 6), in the gas and aqueous phases. The liquid-state environmental effects are included via a simple cavity model and by using the self-consistent reaction field method. The calculations find that the solvent effects are crucial. By this, we mean that a simple cavity model, alone, will be incapable of giving insight into the chemical behavior of such molecules. The short-ranged interactions between the actinyls and their closest water molecules are very strong and involve an appreciable amount of charge transfer, an effect that cannot be included in cavity models. The actinyls form strongly bound complexes with the surrounding water molecules, with n ) 5 being the most stable. Thus, the short-range solvent effects are important. The binding energies of the complexes are very large, and in the gas phase they are about twice as large as in the aqueous phase. Thus, the bulk solvent effects are also important. Any reactivity of the actinyls with other species will thus be impeded by the existence of such strongly bound complexes, and the solvent will play an actiVe role in such phenomena. Regarding the chemical behavior of the actinyls in aqueous solution, our studies provide preliminary evidence that there will be no qualitative and very little quantitative difference between the uranium and plutonium species.

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“…The presence of additional (more than three) donor groups causes no significant increase in the stability constants of the actinyl complexes because the additional donors do not form bonds with the actinyl cation. Interesting exceptions to this general observation are the pentacoordinate calixarene-based ligands (Shinkai et al, 1987;Guilbaud and Wipff, 1993a), which have the proper geometry to be strong and highly selective complexants for the actinyl(VI) ions.…”

Section: Coordination Numbersmentioning

confidence: 78%