Wipff Georges

Wipff Georges
University of Strasbourg | UNISTRA ·  Institut de Chimie de Strasbourg

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283
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Publications (283)
Article
The formation of aqueous biphasic systems (ABSs) based on aqueous ionic liquid (IL)/salt mixtures has been investigated via MD simulations (with IL butyl-methyl-imidazolium triflate; salts NaCl, CsCl, SrCl2, EuCl3). The analysis of ion distributions, solvation and mutual interactions during the dynamics reveals the heterogeneity of all solutions, d...
Article
The mechanism by which Zr-substituted and other transition metal-substituted polyoxometalates form covalently linked dimers has been analyzed by means of static density functional theory and Car−Parrinello molecular dynamics simulations. The study identifies the Zr-aqua-hydro anion, [W5O18Zr(OH)(H2O)]³⁻, as the active species under basic conditions...
Article
Purely organic radical ions dimerize in solution at low temperature, forming long, multicenter bonds, despite the metastability of the isolated dimers. Here, we present the first computational study of these π-dimers in solution, with explicit consideration of solvent molecules and finite temperature effects. By means of force-field and ab initio m...
Article
We studied by molecular dynamics “MD” and potential of mean force “PMF” simulations the complexation of M+ alkali picrates by 18C6 in the 90:10 chloroform/methanol mixture and in its neat solvent components, for comparison. The mixture is found to be microscopically heterogeneous, owing to self-aggregation of methanol molecules into labile nano-dom...
Article
In order to get microscopic views of what happens at the water/chloroform interface upon selective extraction of alkali cations (M+ = Na+, K+, Cs+) by the 18-crown-6 macrocycle “18C6”, we studied by MD and potential of mean force “PMF” simulations their complexation in the source phase (water) and at the interface, and the interface crossing by the...
Article
Full-text available
We report DFT static and dynamic studies on uranyl complexes [UO2(NO3)x(H2O)yLz]2−x involved in the uranyl extraction from water to an “oil” phase (hexane) by an amide ligand L (N,N-dimethylacetamide). Static DFT results “in solution” (continuum SMD models for water and hexane) predict that the stepwise formation of [UO2(NO3)2L2] from the UO2(H2O)5...
Article
The complexation of alkylammonium RNH3+ cations by 18-crown-6 "18C6" is studied by molecular dynamics "MD" and potential of mean force "PMF" simulations in different solvents (methanol, chloroform, the 90:10 chloroform/methanol mixture, water) and at the chloroform/ water interface. The free energies of association Gass, obtained with two charge m...
Article
Quantum chemical calculations are used to derive distributed polarizability models sufficiently accurate and compact to be used in classical Molecular Dynamics simulations of imidazolium-based room temperature ionic liquids. Two distributed polarizability models are fitted to reproduce the induction energy of three imidazolium cations (1,3-dimethyl...
Article
We report a molecular dynamics (MD) study of biphasic systems involved in the liquid-liquid extraction of uranyl nitrate by tri-n-butylphosphate (TBP) to hexane, from "pH neutral" or acidic (3 M nitric acid) aqueous solutions, to assess the model dependence of the surface activity and partitioning of TBP alone, of its UO2(NO3)2(TBP)2 complex, and o...
Article
Static density functional theory (DFT) calculations with a continuous solvent model as well as classical and Car-Parrinello molecular dynamics (MD) simulations with explicit solvent molecules were performed to study the nature of Zr-monosubstituted monomeric and dimeric polyoxometalates (POMs) in water at different pHs. We have analyzed Zr-aqua, -h...
Article
Full-text available
Static ab initio and density-functional computations, as well as Car-Parrinello molecular dynamics simulations in aqueous solution are reported for [UO2(OH)(κ(2)-O2)(H2O)2](-) and [UO2(OH)2(κ(1)-O2H)(H2O)](-). Whereas the κ(1)-hydroperoxo isomer is found to be more stable than the κ(2)-peroxo form in the gas phase, the order of stability is reverse...
Article
We report a molecular dynamics study of biphasic systems involved in the liquid-liquid extraction of uranyl nitrate by a monoamide ligand (L = N,N-di(2-ethylhexyl)isobutyramide, DEHiBA) to hexane, from pH neutral or acidic (3 M nitric acid) aqueous solutions. We first describe the neat interfaces simulated with three electrostatic models, one of wh...
Article
We report molecular dynamics (MD) simulations of aqueous solutions of Keggin heteropolyacids XWn nH3O+ (XWn = [PW12O40]3, [SiW12O40]4, and [AlW12O40]5), the aim of which was to investigate whether the anions increasingly repulse each other in water when their charge increases from 3 to 5. The MD and PMF (potential of mean force) results indicate th...
Article
Bistriazinyl-phenantroline "BTPhen" ligands L display the remarkable feature to complex trivalent lanthanide and actinide ions, with a marked selectivity for the latter. We report on molecular dynamics studies of tetrasubstituted X4BTPhens: L4+ (X = +Et3NCH2), L4- (X = -SO3Ph) and L0 (X = CyMe4) and their complexes with EuIII in binary octanol / wa...
Article
Car-Parrinello molecular dynamics (CMPD) simulations and static computations are reported at the BLYP level of density functional theory (DFT) for mixed [LaCl(x)(H(2)O)(y)(MeCN)(z)](3-x) complexes in aqueous and nonaqueous solution (acetonitrile). Both methodologies predict coordination numbers (i.e., x + y + z) that are successively lower than nin...
Article
We report a molecular dynamics study on the EuBrn3-n complexes (n=0 to 6) formed upon complexation of Br- by Eu-3+ in the [BMI][PF6], [BMI][Tf2N] and [MeBu3N][Tf2N] ionic liquids (ILs), to compare the effect of the IL anion (PF6- versus Tf2N-), the IL cation (BMI+ versus MeBu3N+) and the IL humidity on their solvation and stability. In dry solution...
Article
Full-text available
We have studied the extraction of four HA acids (HNO(3), HReO(4), HClO(4), HCl) to a hydrophobic ionic liquid (IL) 1-butyl-3-methylimidazolium-bis(trifluoromethanesulfonyl)amide (BMI(+) Tf(2)N(-)) at room temperature, in a wide range of acidic concentrations in water. The effect of tributylphosphate (TBP) as co-solvent is investigated. According to...
Article
The complexation of perrhenate (ReO(4)(-)) anions by the uranyl (UO(2)(2+)) cation has been investigated by joint molecular dynamics simulations and spectroscopic (UV-vis, TRLFS, and EXAFS) studies in aqueous solution, acetonitrile, and three ionic liquids (ILs), namely, [Bmi][Tf(2)N], [Me(3)BuN][Tf(2)N], and [Bu(3)MeN][Tf(2)N] that are based on th...
Article
Optimizations at the BLYP and B3LYP levels are reported for the mixed uranyl chloro/water/acetonitrile complexes [UO(2)Cl(n)(H(2)O)(x)(MeCN)(5-n-x)](2-n) (n = 1-3) and [UO(2)Cl(n)(H(2)O)(x)(MeCN)(4-n-x)](2-n) (n = 2-4), in both the gas phase and a polarizable continuum modeling acetonitrile. Car-Parrinello molecular dynamics (CPMD) simulations have...
Article
First-principles and purely classical molecular dynamics (MD) simulations for complexes of the uranyl ion (UO(2)(2+)) are reviewed. Validation of Car-Parrinello MD simulations for small uranyl complexes in aqueous solution is discussed. Special attention is called to the mechanism of ligand-exchange reactions at the uranyl centre and to effects of...
Article
BTBPs represent an important class of tetradentate heterocyclic ligands with N-donor binding sites that have been recently developed to separate trivalent actinides from lanthanides. We first investigate by QM calculations the conformational properties, basicity and complexation energies with Eu(NO(3))(3), comparing BTBP derivatives with alkyl subs...
Article
We report a molecular dynamics study on pertechnetic acid (PTA) extraction from water to an oil phase containing either pure TBP (tri-n-butyl phosphate) or a TBP/n-hexane mixture, with the main aim to understand the state of the acid (associated TcO(4)H vs dissociated TcO(4)(-)H(+)) and its "complexation" by TBP. Experimentally, Tc(VII) is extracte...
Article
Optimizations at the BLYP and B3LYP levels are reported for mixed uranyl-water/acetonitrile complexes [UO(2)(H(2)O)(5-n)(MeCN)(n)](2+) (n = 0-5), in both the gas phase and a polarizable continuum modeling acetonitrile. Car-Parrinello molecular dynamics (CPMD) simulations have been performed for these complexes in the gas phase, and for selected spe...
Article
Bis(1,2-4 triazin-3-yl)pyridines "BTPs'' represent a new class of N-donor extracting agents that separate trivalent actinides and lanthanides from nuclear waste solutions with high An/Ln separation factors. We report here QM calculations on the effect of R-para-BTP substituents on the protonation and complexation energies of these ligands (1 : 1 an...
Article
To investigate whether polyoxometallate α-PW12O403− Keggin anions (noted PW3−) repulse each other in water, we calculated the changes in free energy ΔG(d) as a function of the P…P distance d (potential of mean force “PMF” calculations). As the anions approach each other, the free energy profiles are found to be quite flat, with a tiny minimum at ca...
Article
A novel approach for the optimisation of extractants for the actinide(III)/lanthanide(III) separation is presented. Two BTP ligands are synthesised carrying OMe or Cl moieties on the pyridine ring, thus altering the electronic structure of the aromatic system. The influence of functionalisation on the ligand basicity is determined both spectroscopi...
Article
In order to gain microscopic insights into the extraction mechanism of strontium cations by 18-crown-6 (18C6) to room temperature ionic liquids (ILs), we simulated by molecular dynamics (MD) strontium complexes in neat ionic liquids and at their interfaces with water. We compared two ILs, based on the PF(6)(-) anion and either 1-butyl-3-methylimida...
Article
Heterocyclic N-donor ligands based on the bistriazinylpyridine (BTPs) skeleton have been recently developed to separate trivalent actinides from lanthanides by liquid-liquid extraction from nuclear solutions. In this paper, we report molecular dynamics investigations on BTPs in water-"oil" biphasic systems (oil = hexane + octanol vs. hexane vs. nit...
Article
A substructural molecular fragment (SMF) method has been developed to model the relationships between the structure of organic molecules and their thermodynamic parameters of complexation or extraction. The method is based on the splitting of a molecule into fragments, and on calculations of their contributions to a given property. It uses two type...
Article
By coupling EXAFS, UV-vis spectroscopy, and molecular dynamics and quantum mechanical calculations, we studied the competitive complexation of uranyl cations with nitrate and chloride ions in a water immiscible ionic liquid (IL), C(4)mimTf(2)N (C(4)mim(+): 1-butyl-3-methyl-imidazolium; Tf(2)N(-) = (CF(3)SO(2))(2)N)(-): bis(trifluoromethylsulfonyl)i...
Article
Ab initio calculations have been used to adapt the AMBER force field to three organic dyes (CI disperse red 82, CI disperse blue 60 and CI disperse yellow 211) that are interesting for industrial textile dying processes in supercritical carbon dioxide. For each dye molecule in carbon dioxide solution, Molecular Dynamics simulations with periodic bo...
Article
Norbadione A (NBA) is a pigment present in edible mushrooms which is presumed to selectively complex Cs(+) cations. Due to a very uncommon complexation mechanism, we used a combination of several experimental techniques, including (1)H-NMR, (133)Cs-NMR, isothermal calorimetric, potentiometric titrations and molecular dynamics MD simulations to dete...
Article
A recent computational study (Chaumont, A; Wipff, G. Phys. Chem. Chem. Phys. 2008, 10, 6940) showed that, in spite of their high charge and spherical shape, polyoxometalate α-PW12O403− Keggin anions PW3− can “attract each other” and form oligomers in water. This led us to speculate that these anions should also display surface-active properties, a...
Article
The inclusion of NH(4)(+) as counterions in Car-Parrinello molecular dynamics (CPMD) simulations of anionic uranyl(VI) complexes is proposed as a viable approach to modeling "real" aqueous solutions. For [UO(2)F(4)(H(2)O)](2-) in water, it is shown that the inclusion of two NH(4)(+) ions strengthens the bond between uranyl and the water ligand by c...
Article
We report a molecular dynamics study of key species involved in the liquid-liquid extraction of the cesium picrate salt by an important extractant molecule L (the 1,3-alternate-dimethoxy-calix[4]arene-crown-6) at the chloroform-water interface, with the main aim being to investigate the effect of (i) the explicit representation of polarization effe...
Article
We report a molecular dynamics study on the solvation of trivalent lanthanide cations Ln((III)) (Ln = La, Eu and Yb) in the [BMI][SCN] and [MeBu(3)N][SCN] ionic liquids (ILs), based respectively on 1-methyl-3-butylimidazolium (BMI(+)) and tributylmethylammonium (MeBu(3)N(+)) cations, and on thiocyanate (SCN(-)) anions. For this purpose we first der...
Article
Mixed uranyl aquo fluoro complexes [UO2(H2O)xFy]2−y (y=1–4; x+y=4, 5) have been optimized with BLYP and B3LYP density functionals in vacuo and in a polarizable continuum modeling bulk water, and have been studied at the BLYP level with Car–Parrinello molecular dynamics (MD) simulations. Using constrained MD simulations and thermodynamic integration...
Article
Aqueous solutions of the polyoxometallate alpha-PW(12)O(40)(3-) Keggin anion "PW(3-)" have been simulated by molecular dynamics, comparing two anion concentrations (0.06 and ca. 0.15 mol l(-1)) and Cs(+), NBu(4)(+), UO(2)(2+), Eu(3+), H(3)O(+) and H(5)O(2)(+) as neutralizing M(n+) counterions. They reveal marked counterion effects of the degree of...
Article
We report a molecular dynamics study of ionic liquids (ILs) at the alpha-quartz(001) surface. The studied ILs are based on the 1-butyl-3-methylimidazolium (BMI(+)) cation and different anions Y(-) (Y = Cl, BF(4), PF(6), and Tf(2)N) of increasing size and hydrophobicity. Two chemically different quartz(001) model surfaces were compared: a fully hydr...
Article
The stepwise addition of 1 to 4 Cl(-) anions to the uranyl cation has been studied via potential of mean force (PMF) calculations in the [BMI][Tf 2N] ionic liquid based on the 1-butyl-3-methylimidazolium cation (BMI(+)) and the bis(trifluoromethylsulfonyl)imide anion (Tf2N(-)). According to these calculations, the four Cl(-) complexation reactions...
Article
We report a molecular dynamics study of propene/water biphasic systems involved in the hydroformylation of propene catalyzed by water soluble rhodium complexes with TPPTS3- ligands (where TPPTS3− is the tris(m-sulfonatophenyl)phosphine ligand), neutralized by Na+ counterions). The neat biphasic system is found to display a quite thin and irregular...
Article
We report a molecular dynamics study of the phase separation of binary 1-hexene/[BMI][PF6] ionic liquid (IL) random mixtures containing four widely used phosphine ligands and their key reaction intermediates involved in the biphasic rhodium-catalyzed hydroformylation of 1-hexene. In all cases, the organic and IL phases separate during the dynamics,...
Article
Mixed uranyl aquo chloro complexes of the type [UO2(H2O)xCly]2-y (y = 1, 2, 3, 4; x + y = 4, 5) have been optimized at the BLYP, BP86, and B3LYP levels of density functional theory in vacuo and in a polarizable continuum modeling bulk water (PCM) and have been studied at the BLYP level with Car-Parrinello molecular dynamics (MD) simulations in the...
Article
We report a quantum mechanical (QM) and classical molecular dynamics (MD) study of the conformational and complexation properties of norbadione-A (NBA), a key pigment involved in the Cs+ complexation by mushrooms. The Z versus E isomers of its pulvinic moieties are compared in their neutral (Pulv0), mono- (Pulv(-1)) and di-deprotonated (Pulv(-2)) s...
Article
We report a molecular dynamics study of chlorinated cobalt bis(dicarbollide) anions [(B(9)C(2)H(8)Cl(3))(2)Co](-)"CCD(-)" in nitrobenzene and at the nitrobenzene-water interface, with the main aim to understand the solution state of these hydrophobic species and why they act as strong synergists in assisted liquid-liquid extraction of metallic cati...
Article
We report a molecular dynamics (MD) study of the effect of a fluorinated lipophilic alcohol (referred to as "cs3" by Delmau et al, Solvent Extr. Ion Exch., 2005, 23, 23) used as a phase modifier in the solvent extraction of Cs(+) NO(3)(-) by a calix[4]arene. It is shown that adding cs3 to a chloroform phase improves the solvation of all partners of...
Article
We report molecular dynamics studies on the solvation of sodium chloride in the 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ionic liquid ([BMI][Tf2N] IL). We first consider the potential of mean force for dissociating a single Na+Cl- ion pair, showing that the latter prefers to be undissociated rather than dissociated (by ca. 9 k...
Article
According to Car-Parrinello molecular dynamics simulations for [UO(2)(NO(3))(3)](-), [UO(2)(NO(3))(4)](2-), and [UO(2)(OH(2))(4-)(NO(3))](+) complexes in the gas phase and in aqueous solution, the nitrate coordination mode to uranyl depends on the interplay between ligand-metal attractions, interligand repulsions, and solvation. In the trinitrate,...
Article
The first coordination sphere of the uranyl cation in room-temperature ionic liquids (ILs) results from the competition between its initially bound counterions, the IL anions, and other anions (e.g., present as impurities or added to the solution). We present a joined spectroscopic (UV-visible and extended X-ray absorption fine structure)-simulatio...
Article
We report a molecular dynamics study of the solvation of UCl(6)(-), UCl(6)(2-), and UCl(6)(3-) complexes in the [BMI][Tf(2)N] and [MeBu(3)N][Tf(2)N] ionic liquid cations based on the same anion (bis(trifluoromethylsulfonyl)imide (Tf(2)N-)) and the butyl-3-methyl-imidazolium+ (BMI+) or methyl-tri-n-butyl-ammonium (MeBu(3)N+) cation, respectively. Th...
Article
We report a molecular dynamics study of biphasic systems involved in the rhodium-catalyzed hydroformylation of 1-hexene in the 1-butyl-3-methyl- imidazolium hexafluorophosphate ionic liquid ([BMI][PF6] IL). We first describe the neat [BMI][PF6] interfaces with hexene (the substrate) and heptanal (the linear reaction product) as organic phases. The...
Article
We report a molecular dynamics study of chlorinated cobalt bis(dicarbollide) anions [(B9C2H8Cl3)2Co]− “CCD−” in octanol and at the octanol–water interface, with the main aim to understand why these hydrophobic species act as strong synergists in assisted liquid–liquid cation extraction. Neat octanol is quite heterogeneous and is found to display du...
Article
We report a molecular dynamics study of the solvation of spherical solutes Sq of ca. 5 Å radius in ionic liquids (ILs) based on the PF6− anion and the 1-butyl-3-methylimidazolium cation (BMI+) or 1-octyl-3-methylimidazolium cation (OMI+), as a function of the sign and magnitude of the charge q=0, ±1, ±2 and ±4 of Sq. The simulations highlight the d...
Article
We report herein a molecular dynamics study of the main species involved in the hydroformylation of higher olefins promoted by cyclodextrins in 1-decene/water biphasic systems at a temperature of 350 K. The two liquids form a well-defined sharp interface of approximately 7 A width in the absence of solute; the decene molecules are generally oriente...
Article
We present a molecular dynamics study of concentrated solutions of K⊂222 cryptates, comparing two counterions X (Chloride Cl versus Picrate Pic) and three solvents (water, acetonitrile, and chloroform), with the main aim to investigate the distribution of the ions in the different solutions. The simulations reveal marked differences from one system...
Article
We report a molecular dynamics (MD) study of the interfacial behavior of key partners involved in the Cs(+) cation extraction by a calix[4]arene-crown-6 host (L), comparing an ionic liquid (IL) to a classical molecular solvent (chloroform) as receiving "oil" phase. The IL is composed of hydrophobic 1-butyl-3-methylimidazolium cations (BMI(+)) and b...
Article
We report a Molecular Dynamics (MD) study of the interface between water and the hygroscopic room temperature Ionic Liquid "IL" [BMI][PF6] (1-butyl-3-methyl-imidazolium hexafluorophosphate), comparing the TIP3P, SPC/E and TIP5P models for water and two IL models where the ions are +/-1 or +/-0.9 charged. A recent MD study (A. Chaumont, R. Schurhamm...
Article
We report molecular dynamics (MD) simulations of the aqueous interface of the hydrophobic [BMI][Tf2N] ionic liquid (IL), composed of 1-butyl-3-methylimidazolium cations (BMI+) and bis(trifluoromethylsulfonyl)imide anions (Tf2N-). The questions of water/IL phase separation and properties of the neat interface are addressed, comparing different liqui...
Article
We report a molecular dynamics study of cobalt bis(dicarbollide) anions [(B(9)C(2)H(8)X(3))(2)Co](-) (XCD(-)) commonly used in liquid-liquid extraction (X = H, Me, Cl, or Br), showing that these anions, although lacking the amphiphilic topology, behave as anionic surfactants. In pure water, they display "hydrophobic attractions", leading to the for...
Article
Results from Car-Parrinello molecular dynamics simulations are reported for [UO2(OH2)5]2+, UO2(NO3)2(OH2)2, and UO2(NO3)2(eta2-tmma) (tmma = tetramethylmalonamide) in the gas phase and in aqueous solution. The distances between uranyl and neutral ligands such as water and tmma are decreased by up to 0.2 angstroms upon hydration, whereas those betwe...
Article
We report a molecular dynamics study of halide anions X− and their inclusion complexes X− ⊂ L4+ with a macrotricyclic tetrahedral host L4+ built from four quaternary ammonium sites, in an ionic liquid (IL) based on the 1-butyl-3-methylimidazolium (BMI+) cation and the PF6− anion. The “dry” and “humid” forms of the [BMI][PF6] IL are compared, showin...
Article
Using molecular dynamics (MD) simulations, we investigate the interfacial distribution of partners involved in the phase transfer rhodium catalyzed hydroformylation of olefins promoted by beta-cyclodextrins (beta-CDs). The beta-CDs, the reactant (alkene), product (aldehyde), several rhodium complexes (the catalyst, its precursor, and its alkene add...
Article
Full-text available
The solvation of the [UO(2)(NO(3))(CMPO)](+) and [UO(2)(NO(3))(2)(CMPO)(2)] complexes (CMPO = octyl(phenyl)-N,N-diisobutylmethylcarbamoyl phosphine oxide) is investigated by molecular dynamics in the "dry" and "humid" forms of a room temperature ionic liquid (IL) based on the 1-butyl-3-methylimidazolium (BMI(+)) cation and the hexafluorophosphate (...
Article
We report a molecular dynamics study on the solvation of M+ (Na+ to Cs+) alkali cations and of their LM+ complexes with a calix[4]arene host (L = 1,3-dimethoxy-calix[4]arene-crown-6 in the 1,3-alternate conformation) in the [BMI][PF6] and [BMI][Tf2N] room-temperature ionic liquids "ILs" based on the BMI+ (1-butyl-3-methylimidazolium) cation. The co...
Article
Combining spectroscopic techniques (TRES and EXAFS) and molecular dynamics simulations, we have investigated the state of trivalent europium dissolved in room-temperature ionic liquids (RTILs), as a function of the RTIL anion and in the presence of added chloride anions. The studied RTILs are based on the 1-butyl-3-methyl-imidazolium (Bumim+) catio...
Article
We report studies on the Pd(II) and Ag(I) complexation and extraction by tetraalkyl(tolyl)thiomethylcalix[4]arenes (1a–c) stabilized in the cone conformation, and by the stereochemically mobile tetraalkyl(tolyl)thiomethylcalix[6]arenes (2a, b). These are found to be 100–1000 times more efficient as extractants of nitric and nitrous forms of Pd(II)...
Article
Density-functional-based Car-Parrinello molecular dynamics (CPMD) simulations have been performed for the ionic liquid 1,3-dimethylimidazolium chloride, [dmim]Cl, at 438 K. The local structure of the liquid is described in terms of various partial radial distribution functions and anisotropic spatial distributions, which reveal a significant extent...
Article
We report a molecular dynamics study of the interface between water and (macroscopically) water-immiscible room-temperature ionic liquids "ILs", composed of PF6(-) anions and butyl- versus octyl-substituted methylimidazolium+ cations (noted BMI+ and OMI+). Because the parameters used to simulate the pure ILs were found to exaggerate the water/IL mi...
Article
Water dissociation from [UO2(OH2)5]2+ is studied with Car-Parrinello molecular dynamics simulations (using the BLYP density functional) in the gas phase and in aqueous solution. Free energies, DeltaA, are estimated from pointwise thermodynamic integration using one U-O(H2) distance as a reaction coordinate. While an isomeric, four-coordinate comple...
Article
A new ligand, LC, bis-[(6'-carboxy-2,2'-bipyridine-6-yl)]phenylphosphine oxide, in which the tridentate 6-carboxy-2,2'-bipyridyl arms are directly linked to a phenylphosphine oxide fragment, has been synthesized. The corresponding [Ln.LC]Cl.xH2O complexes (Ln = Eu, x = 4, and Tb, x = 3) were isolated from solutions containing equimolar amounts of L...
Article
We present a molecular dynamics study of the K extraction by the 222 cryptand, comparing different counterions X at the supercritical-CO2/water interface: X = picrate “Pic” vs perfluorooctanoate “PFO” vs chlorinated cobalt dicarbollides CCD vs Cl. The distribution of the free KX salts is also investigated, showing different distributions, depending...
Article
Two different strategies were used to synthesize tri(2-alkoxy-5-nitrophenyl)methanes 6a,b. The X-ray structures of 6a and its precursor 5 show the molecules in a conformation with a syn-orientation of the nitro and alkoxy groups. Hydrogenation and acylation by the appropriate active ester gave the corresponding tri-CMPO derivatives 4a,b. Their abil...
Article
We report theoretical studies on the complexation of uranyl nitrate and the dissolution of nitric acid in supercritical CO2 by TBP. According to quantum mechanical calculations, TBP (modeled by trimethyl phosphate TMP) displays stronger hydrogen-bonding interactions with HNO3 than with H2O, and this has been modeled in force-field calculations. Dif...
Article
Full-text available
We report a molecular dynamics study on the solvation of EuFn(3-n) complexes in the [BMI][PF6] ionic liquid, composed of 1-butyl-3-methyl-imidazolium+ cations and PF6- anions. It is found that the most fluorinated complex in the liquid should be the EuF6(3-) species. In solution the EUF10(7-) and EuF7(4-) complexes indeed loose, respectively, 4 and...
Article
According to molecular dynamics simulations, uncomplexed malonamide ligands L and their neutral Eu(NO3)3L2 or charged EuL4(3+) complexes are surface active and adsorb at a water-"oil" interface, where "oil" is modeled by chloroform. Aqueous solvation at the interface is found to induce a trans to gauche rearrangement of the carbonyl groups, i.e., t...
Article
We report theoretical investigations on the effect of H --> F substitution in acetylacetonate ligands in order to understand why fluorination promotes the extraction of uranyl to supercritical CO(2) with a marked synergistic effect of tri-n-butyl phosphate "TBP". The neutral LH and deprotonated L(-) forms of the ligand, and the uranyl complexes UO(...
Article
We report a molecular dynamics study of the solvation of 18-crown-6 (“18C6”) and of its K+, Cs+ and Sr2+ complexes in a room-temperature ionic liquid (IL) based on 1-butyl-3-methyl-imidazolium+, PF6−. “Dry” [BMI][PF6] versus “humid” [BMI][PF6][H2O] models of the IL are compared, demonstrating the importance of solvent humidity on the solvation prop...
Article
There have always been tight connections between supramolecular and theoretical chemistry. In the early seventies, quantum chemists introduced the "supermolecule" approach to analyze the strength and nature of the non-covalent interactions which assemble simple systems like the water dimer or water-ion adducts in the gas phase, and presumably large...
Article
We report molecular dynamics studies on the effect of CCD- (chlorinated cobalt-dicarbollide) anions on the Eu3+ lanthanide cation extraction by a calix[4]arene-CMPO ligand L, focusing on the water-'oil' interface, where 'oil' is modelled by chloroform. The free L ligand and its EuL3+ complex are found to adsorb and to concentrate at the interface,...
Article
The harmonic vibrational frequencies of the complex of H3O+ with 18-crown-6 are reported at a variety of ab initio (Hartree−Fock and MP2) and density functional levels (gradient-corrected and hybrid functionals). At all levels, two νas(COC) vibrations with large IR intensities are obtained, which are in very good agreement, in terms of both positio...