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ABSTRACT: The iodouranium(iii) complex with two hydrotris(3,5-dimethylpyrazolyl)borate ligands is shown to adopt three closely related forms in the solid state. In addition to the previously reported structure for [U(Tp(Me2))2I], in which one of the pyrazolyl rings coordinates side-on to the U atom, another structure incorporating solvent molecules presents undistorted pyrazol rings, and a third one is the ionic compound [U(Tp(Me2))2]I. The implications of this structural diversity for the recently reported single ion magnet behaviour in this complex are discussed, namely on the basis of quantum chemistry calculations. The main effect of the bonding of the iodine atom to uranium is the increase of the size of the first coordination sphere and lowering of the symmetry of the molecule, resulting in a smaller crystal field splitting.
Dalton Transactions 05/2013; · 3.84 Impact Factor
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ABSTRACT: A new bis(phenol)dimethyltetraazamacrocycle, 1,8-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-4,11-dimethyl-1,4,8,11-tetraazacyclotetradecane (H2{(tBu2PhO)2Me2Cyclam}) (1), is described. Deprotonation of 1 with sodium or potassium hydrides afforded Na2{(tBu2PhO)2Me2Cyclam} (2) and K2{(tBu2PhO)Me2Cyclam} (3), respectively. Reactions of 2 or 3 with yttrium or lanthanide trichlorides led to the formation of neutral rare earth metal complexes of general formula [{(tBu2PhO)2Me2Cyclam}LnCl] (Ln = Y (4), La (5), Sm (6), Yb (7)) in moderate to high yields. The molecular structures of 4–7 were determined by single-crystal X-ray diffraction analysis and reveal that the ligand's denticity depends on the size of the metal ions. The smaller Y3+ and Yb3+ lead to distorted octahedral geometries where the dianionic ligand acts as pentadentate, while the larger ions, La3+ and Sm3+, form capped trigonal prismatic complexes with the cyclam derivative acting as a hexadentate chelator.
Journal of Organometallic Chemistry 04/2013; 728:57. · 2.38 Impact Factor
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ABSTRACT: The homoleptic compounds [U(salan-R2)2] (R = Me (1), tBu (2)) were prepared in high yield by salt-metathesis reactions between UI4(L)2 (L = Et2O, PhCN) and 2 equiv of [K2(salan-R2)] in THF. In contrast, the reaction of the tetradentate ligands salan-R2 with UI3(THF)4 leads to disproportionation of the metal and to mixtures of U(IV) [U(salan-R2)2] and [U(salan-R2)I2] complexes, depending on the ligand to M ratio. The reaction of K2salan-Me2 ligand with U(IV) iodide and chloride salts always leads to mixtures of the homoleptic bis-ligand complex [U(salan-Me2)2] and heteroleptic complexes [U(salan-Me2)X2] in different organic solvents. The structure of the heteroleptic complex [U(salan-Me2)I2(CH3CN)] (4) was determined by X-ray studies. Heteroleptic U(IV) and Th(IV) chloride complexes were obtained in good yield using the bulky salan-tBu2 ligand. The new complexes [U(salan-tBu2)Cl2(bipy)] (5) and [Th(salan-tBu2)Cl2(bipy)] (8) were crystallographically characterized. The salan-tBu2 halide complexes of U(IV) and Th(IV) revealed good precursors for the synthesis of stable dialkyl complexes. The six-coordinated alkyl complexes [Th(salan-tBu2)(CH2SiMe3)2] (9) and [U(salan-tBu2)(CH2SiMe3)2] (10) were prepared by addition of LiCH2SiMe3 to the chloride precursor in toluene, and their solution and solid-state structures (for 9) were determined by NMR and X-ray studies. These complexes are stable for days at room temperature. Preliminary reactivity studies show that CO2 inserts into the An–C bond to afford a mixture of carboxylate products. In the presence of traces of LiCl, crystals of the dimeric insertion product [Th2Cl(salan-tBu2)2(μ-η1:η1-O2CCH2SiMe3)2(μ-η1:η2-O2CCH2SiMe3)] (11) were isolated. The structure shows that CO2 insertion occurs in both alkyl groups and that the resulting carboxylate is easily displaced by a chloride anion.
Organometallics 12/2012; 32(5):1409. · 3.96 Impact Factor
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ABSTRACT: ABSTRACT Fourier transform ion cyclotron resonance mass spectrometry was used to characterize the gas-phase reactivity of Hf dipositive ions, Hf2+ and HfO2+, towards several oxidants: thermodynamically facile O-atom donor N2O, ineffective donor CO, and intermediate donors O2, CO2, NO, and CH2O. The Hf2+ ion exhibited electron transfer with N2O, O2, NO and CH2O, reflecting the high ionization energy of Hf+. The HfO2+ ion was produced by O-atom transfer to Hf2+ from N2O, O2 and CO2, and the HfO22+ ion by O-atom transfer to HfO2+ from N2O; these reactions were fairly efficient. Density functional theory revealed the structure of HfO22+ as a peroxide. The HfO22+ ion reacted by electron transfer with N2O, CO2, and CO to give HfO2+. Estimates were made for the second ionization energies of Hf (14.5 ± 0.5 eV), HfO (14.3 ± 0.5 eV), and HfO2 (16.2 ± 0.5 eV ), and also for the bond dissociation energies, D[Hf2+-O] = 686 ± 69 kJ mol-1 and D[OHf2+-O] = 186 ± 98 kJ mol-1. The computed bond dissociation energies, 751 and 270 kJ mol-1, respectively, are within these experimental ranges. Additionally, it was found that HfO22+ oxidized CO to CO2 and is thus a catalyst in the oxidation of CO by N2O; and that Hf2+ activates methane to produce a carbene, HfCH22+.
The Journal of Physical Chemistry A 11/2012; · 2.95 Impact Factor
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ABSTRACT: Activation of uranyl(V) oxo bonds in the gas phase is demonstrated by reaction of U(16)O(2)(+) with H(2)(18)O to produce U(16)O(18)O(+) and U(18)O(2)(+). In contrast, neptunyl(V) and plutonyl(V) are comparatively inert toward exchange. Computed potential energy profiles (PEPs) reveal a lower yl oxo exchange transition state for uranyl(V)/water as compared with neptunyl(V)/water and plutonyl(V)/water. A correspondence between oxo exchange rates in gas phase and acid solutions is apparent; the contrasting oxo exchange rates of UO(2)(+) and PuO(2)(+) are considered in the context of covalent bonding in actinyls. Hydroxo exchange of U(16)O(2)((16)OH)(+) with H(2)(18)O to give U(16)O(2)((18)OH)(+) proceeded much faster than oxo exchange, in accord with a lower computed transition state for OH exchange. The PEP for the addition of H(2)O to UO(2)(+) suggests that both UO(2)(+)·(H(2)O) and UO(OH)(2)(+) should be considered as potential products.
Journal of the American Chemical Society 09/2012; 134(37):15488-96. · 9.91 Impact Factor
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ABSTRACT: [U(Tp(Me2))(2)I] exhibits at low temperatures single molecule magnet (SMM) behaviour comparable to its bipyridine derivative and related single ion U(iii) complexes recently reported as SMMs. The trend of variation of the energy barrier for the magnetic relaxation in these compounds is well reproduced by quantum chemistry calculations.
Dalton Transactions 08/2012; 41(44):13568-71. · 3.84 Impact Factor
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ABSTRACT: The following monopositive actinyl ions were produced by electrospray ionization of aqueous solutions of An(VI)O(2)(ClO(4))(2) (An = U, Np, Pu): U(V)O(2)(+), Np(V)O(2)(+), Pu(V)O(2)(+), U(VI)O(2)(OH)(+), and Pu(VI)O(2)(OH)(+); abundances of the actinyl ions reflect the relative stabilities of the An(VI) and An(V) oxidation states. Gas-phase reactions with water in an ion trap revealed that water addition terminates at AnO(2)(+)·(H(2)O)(4) (An = U, Np, Pu) and AnO(2)(OH)(+)·(H(2)O)(3) (An = U, Pu), each with four equatorial ligands. These terminal hydrates evidently correspond to the maximum inner-sphere water coordination in the gas phase, as substantiated by density functional theory (DFT) computations of the hydrate structures and energetics. Measured hydration rates for the AnO(2)(OH)(+) were substantially faster than for the AnO(2)(+), reflecting additional vibrational degrees of freedom in the hydroxide ions for stabilization of hot adducts. Dioxygen addition resulted in UO(2)(+)(O(2))(H(2)O)(n) (n = 2, 3), whereas O(2) addition was not observed for NpO(2)(+) or PuO(2)(+) hydrates. DFT suggests that two-electron three-centered bonds form between UO(2)(+) and O(2), but not between NpO(2)(+) and O(2). As formation of the UO(2)(+)-O(2) bonds formally corresponds to the oxidation of U(V) to U(VI), the absence of this bonding with NpO(2)(+) can be considered a manifestation of the lower relative stability of Np(VI).
Inorganic Chemistry 06/2012; 51(12):6603-14. · 4.60 Impact Factor
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ABSTRACT: Reactions of UI3(THF)4, UCl4 and ThCl4 with 1 equiv. of tris(3,5-dimethylpyrazolyl)methane (Tpm∗) in THF led to the formation of the complexes [U(Tpm∗)I3(THF)] (1), [U(Tpm∗)Cl4] (2) and [Th(Tpm∗)Cl4] (3) in good yields. The NMR spectra indicated symmetrical structures in solution, with equivalent pyrazolyl groups of the Tpm∗ ligand. The X-ray crystal structures of the three complexes were determined and in all cases the metallic centre is seven-coordinated, presenting distorted capped octahedral coordination geometry with near C3v symmetry. In 1, the tridentate pyrazolylmethane ligand and the three iodine atoms define the two staggered triangular faces of the octahedron, respectively, and the latter is capped by the THF oxygen. In 2 and 3, the coordination geometry is similar, with three chlorine atoms defining a triangular face capped by the fourth chlorine.
Inorganica Chimica Acta 04/2012; 385:53. · 1.85 Impact Factor
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ABSTRACT: Hydration of ytterbium (III) halide/hydroxide ions produced by electrospray ionization was studied in a quadrupole ion trap
mass spectrometer and by density functional theory (DFT). Gas-phase YbX2
+ and YbX(OH)+ (X=OH, Cl, Br, or I) were found to coordinate from one to four water molecules, depending on the ion residence time in
the trap. From the time dependence of the hydration steps, relative reaction rates were obtained. It was determined that the
second hydration was faster than both the first and third hydrations, and the fourth hydration was the slowest; this ordering
reflects a combination of insufficient degrees of freedom for cooling the hot monohydrate ion and decreasing binding energies
with increasing hydration number. Hydration energetics and hydrate structures were computed using two approaches of DFT. The
relativistic scalar ZORA approach was used with the PBE functional and all-electron TZ2P basis sets; the B3LYP functional
was used with the Stuttgart relativistic small-core ANO/ECP basis sets. The parallel experimental and computational results
illuminate fundamental aspects of hydration of f-element ion complexes. The experimental observations—kinetics and extent
of hydration—are discussed in relationship to the computed structures and energetics of the hydrates. The absence of pentahydrates
is in accord with the DFT results, which indicate that the lowest energy structures have the fifth water molecule in the second
shell.
KeywordsDensity functional theory–Hydration–Lanthanides–Ytterbium halides–Gas-phase reactions–Kinetics
Theoretical Chemistry Accounts 04/2012; 129(3):575-592. · 2.16 Impact Factor
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ABSTRACT: Gas-phase reactions of Ta(2+) and TaO(2+) with oxidants, including thermodynamically facile O-atom donor N(2)O and ineffective donor CO, as well as intermediate donors C(2)H(4)O (ethylene oxide), H(2)O, O(2), CO(2), NO, and CH(2)O, were studied by Fourier transform ion cyclotron resonance mass spectrometry. All oxidants reacted with Ta(2+) by electron transfer yielding Ta(+), in accord with the high second ionization energy of Ta (ca. 16 eV). TaO(2+) was also produced with N(2)O, H(2)O, O(2), and CO(2), oxidants with ionization energies above 12 eV; CO reacted only by electron transfer. The following charge separation products were also observed: TaN(+) and TaO(+) with N(2)O; and TaO(+) with O(2), CO(2), and CH(2)O. TaOH(2+), formed with H(2)O, reacted with a second H(2)O by proton transfer. TaO(2+) abstracted an electron from N(2)O, H(2)O, O(2), CO(2), and CO. Oxidation of TaO(2+) by N(2)O was also observed to produce TaO(2)(2+); on the basis of density functional theory (DFT) results, this species is a dioxide, {O-Ta-O}(2+). TaO(2)(2+) reacted by electron transfer with N(2)O, CO(2), and CO to give TaO(2)(+). Additionally, it was found that TaO(2)(2+) oxidizes CO to CO(2) and that it acts as a catalyst in the oxidation of CO by N(2)O. TaO(2)(2+) also activates H(2) to form TaO(2)H(2+). On the basis of the rates of electron transfer from N(2)O, CO(2), and CO to Ta(2+), TaO(2+), and TaO(2)(2+), the following estimates were made for the second ionization energies of Ta, TaO, and TaO(2): IE[Ta(+)] = 15.8 ± 0.3 eV, IE[TaO(+)] = 16.0 ± 0.5 eV, and IE[TaO(2)(+)] = 16.9 ± 0.4 eV. These IEs, together with recently reported bond dissociation energies, D[Ta(+)-O] and D[OTa(+)-O], result in the following bond energies: D[Ta(2+)-O] = 657 ± 58 kJ mol(-1) and D[OTa(2+)-O] = 500 ± 63 kJ mol(-1), the first of which is in good agreement with the value obtained by DFT.
The Journal of Physical Chemistry A 03/2012; 116(14):3534-40. · 2.95 Impact Factor
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ABSTRACT: The addition of 2,2'-bipyridine to [U(Tp(Me2))(2)I] (1) results in the displacement of the iodide and the formation of the cationic uranium(III) complex [U(Tp(Me2))(2)(bipy)]I (2). This compound was isolated as a dark-green solid in good yield and characterized by IR and NMR spectroscopies, and its molecular structure was determined by single-crystal X-ray diffraction. Studies of its magnetic properties revealed a frequency dependence of magnetization with a blocking temperature of 4.5 K and, at lower temperatures, a slow relaxation of magnetization with an energy barrier of 18.2 cm(-1), characteristic of single-molecule-magnet behavior.
Inorganic Chemistry 09/2011; 50(20):9915-7. · 4.60 Impact Factor
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ABSTRACT: Small alkanes (methane, ethane, propane, n-butane) and alkenes (ethene, propene, 1-butene) were used to probe the gas-phase reactivity of doubly charged actinide cations, An(2+) (An = Th, Pa, U, Np, Pu, Am, Cm), by means of Fourier transform ion cyclotron resonance mass spectrometry. Different combinations of doubly and singly charged ions were observed as reaction products, comprising species formed via metal-ion induced eliminations of small molecules, simple adducts and ions resulting from electron, hydride or methide transfer channels. Th(2+), Pa(2+), U(2+) and Np(2+) preferentially yielded doubly charged products of hydrocarbon activation, while Pu(2+), Am(2+) and Cm(2+) reacted mainly through transfer channels. Cm(2+) was also capable of forming doubly charged products with some of the hydrocarbons whereas Pu(2+) and Am(2+) were not, these latter two ions conversely being the only for which adduct formation was observed. The product distributions and the reaction efficiencies are discussed in relation to the electronic configurations of the metal ions, the energetics of the reactions and similar studies previously performed with doubly charged lanthanide and transition metal cations. The conditions for hydrocarbon activation to occur as related to the accessibility of electronic configurations with one or two 5f and/or 6d unpaired electrons are examined and the possible chemical activity of the 5f electrons in these early actinide ions, particularly Pa(2+), is considered.
Physical Chemistry Chemical Physics 08/2011; 13(41):18322-9. · 3.57 Impact Factor
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ABSTRACT: Laser evaporation of carbon rich uranium/carbon alloy targets into condensing argon or neon matrix samples gives weak infrared absorptions that increase on annealing, which can be assigned to new uranium carbon bearing species. New bands at 827.6 cm(-1) in solid argon or 871.7 cm(-1) in neon become doublets with mixed carbon 12 and 13 isotopes and exhibit the 1.0381 carbon isotopic frequency ratio for the UC diatomic molecule. Another new band at 891.4 cm(-1) in argon gives a three-band mixed isotopic spectrum with the 1.0366 carbon isotopic frequency ratio, which is characteristic of the anti-symmetric stretching vibration of a linear CUC molecule. No evidence was found for the lower energy cyclic U(CC) isomer. Other bands at 798.6 and 544.0 cm(-1) are identified as UCH, which has a uranium-carbon triple bond similar to that in UC. Evidence is found for bicyclic U(CC)(2) and tricyclic U(CC)(3). This work shows that U and C atoms react spontaneously to form the uranium carbide U≡C and C≡U≡C molecules with uranium-carbon triple bonds.
The Journal of chemical physics 06/2011; 134(24):244313. · 3.09 Impact Factor
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ABSTRACT: The gas-phase thermochemistry of actinide monosulfides, AnS, was investigated experimentally and theoretically. Fourier transform ion cyclotron resonance mass spectrometry was employed to study the reactivity of An(+) and AnO(+) (An = Th, Pa, U, Np, Pu, Am and Cm) with CS(2) and COS, as well as the reactivity of the produced AnS(+) with oxidants (COS, CO(2), CH(2)O and NO). From these experiments, An(+)-S bond dissociation energies could be bracketed. Density functional theory studies of the energetics of neutral and monocationic AnS (An = Ac, Th, Pa, U, Np, Pu, Am and Cm) provided values for bond dissociation energies and ionization energies; the computed energetics of neutral and monocationic AnO were also obtained for comparison. The theoretical data, together with comparisons with known An(+)-O bond dissociation energies and M(+)-S and M(+)-O dissociation energies for the early transition metals, allowed for the refining of the An(+)-S bond dissociation energy ranges obtained from experiment. Examination of the reactivity of AnS(+) with dienes, coupled to comparisons with reactivities of the AnO(+) analogues, systematic considerations and the theoretical results, allowed for the estimation of the ionization energies of the AnS; the bond dissociation energies of neutral AnS were consequently derived. Estimates for the case of AcS were also made, based on correlations of the data for the other An and the electronic energetics of neutral and ionic An. The nature of the bonding in the elementary molecular actinide chalcogenides (oxides and sulfides) is discussed, based on both the experimental data and the computed electronic structures. DFT calculations of ionization energies for the actinide atoms and the diatomic sulfides and oxides are relatively reliable, but the calculation of bond dissociation energies is not uniformly satisfactory, either with DFT or CCSD(T). A key conclusion from both the experimental and theoretical results is that the 5f electrons do not substantially participate in actinide-sulfur bonding. We emphasize that actinides form strikingly strong bonds with both oxygen and sulfur.
Physical Chemistry Chemical Physics 06/2011; 13(28):12940-58. · 3.57 Impact Factor
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ABSTRACT: The gas-phase reactions of two dipositive actinide ions, Th(2+) and U(2+), with CH(4), C(2)H(6), and C(3)H(8) were studied by both experiment and theory. Fourier transform ion cyclotron resonance mass spectrometry was employed to study the bimolecular ion-molecule reactions; the potential energy profiles (PEPs) for the reactions, both observed and nonobserved, were computed by density functional theory (DFT). The experiments revealed that Th(2+) reacts with all three alkanes, including CH(4) to produce ThCH(2)(2+), whereas U(2+) reacts with C(2)H(6) and C(3)H(8), with different product distributions than for Th(2+). The comparative reactivities of Th(2+) and U(2+) toward CH(4) are well explained by the computed PEPs. The PEPs for the reactions with C(2)H(6) effectively rationalize the observed reaction products, ThC(2)H(2)(2+) and UC(2)H(4)(2+). For C(3)H(8) several reaction products were experimentally observed; these and additional potential reaction pathways were computed. The DFT results for the reactions with C(3)H(8) are consistent with the observed reactions and the different products observed for Th(2+) and U(2+); however, several exothermic products which emerge from energetically favorable PEPs were not experimentally observed. The comparison between experiment and theory reveals that DFT can effectively exclude unfavorable reaction pathways, due to energetic barriers and/or endothermic products, and can predict energetic differences in similar reaction pathways for different ions. However, and not surprisingly, a simple evaluation of the PEP features is insufficient to reliably exclude energetically favorable pathways. The computed PEPs, which all proceed by insertion, were used to evaluate the relationship between the energetics of the bare Th(2+) and U(2+) ions and the energies for C-H and C-C activation. It was found that the computed energetics for insertion are entirely consistent with the empirical model which relates insertion efficiency to the energy needed to promote the An(2+) ion from its ground state to a prepared divalent state with two non-5f valence electrons (6d(2)) suitable for bond formation in C-An(2+)-H and C-An(2+)-C activated intermediates.
Journal of the American Chemical Society 01/2011; 133(6):1955-70. · 9.91 Impact Factor
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ABSTRACT: In this chapter we review the spectroscopic data for actinide molecules and the reaction dynamics for atomic and molecular
actinides that have been examined in the gas phase or in inert cryogenic matrices. The motivation for this type of investigation
is that physical properties and reactions can be studied in the absence of external perturbations (gas phase) or under minimally
perturbing conditions (cryogenic matrices). This information can be compared directly with the results from high-level theoretical
models.
10/2010: pages 4079-4156;
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ABSTRACT: Laser evaporation of carbon-rich uranium/carbon alloys followed by atom reactions in a solid argon matrix and trapping at 8 K gives weak infrared absorptions for CUO at 852 and 804 cm(-1). A new band at 827 cm(-1) becomes a doublet with mixed carbon 12 and 13 isotopes and exhibits the 1.0381 isotopic frequency ratio, which is appropriate for the UC diatomic molecule, and another new band at 891 cm(-1) gives a three-band mixed isotopic spectrum with the 1.0366 isotopic frequency ratio, which is characteristic of the linear CUC molecule. CASPT2 calculations with dynamical correlation find the C[triple bond]U[triple bond]C ground state as linear 3Sigma(u)+ with 1.840 A bond length and molecular orbital occupancies for an effective bond order of 2.83. Similar calculations with spin-orbit coupling show that the U[triple bond]C diatomic molecule has a quintet (Lambda = 5, Omega = 3) ground state, a similar 1.855 A bond length, and a fully developed triple bond of 2.82 effective bond order.
Journal of the American Chemical Society 06/2010; 132(24):8484-8. · 9.91 Impact Factor
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ABSTRACT: Bimolecular reactions of uranium oxide molecular anions with methanol have been studied experimentally, by Fourier transform ion cyclotron resonance mass spectrometry, and computationally, by density functional theory (DFT). The primary goals were to provide fundamental insights into mechanistic and structural details of model reactions of uranium oxides with organics, and to examine the validity of theoretical modeling of these types of reactions. The ions UO(3)(-), UO(4)(-), and UO(4)H(-) each reacted with methanol to give a singular product; the primary products each exhibited sequential reactions with two additional methanol molecules to again give singular products. The observed reactions were elimination of water, formaldehyde, or hydrogen, and in one case addition of a methanol molecule. The potential energy profiles were computed for each reaction, and isotopic labeling experiments were performed to probe the validity of the computed mechanisms and structures-in each case where the experiments could be compared with the theory there was concurrence, clearly establishing the efficacy of the employed DFT methodologies for these and related reaction systems. The DFT results were furthermore in accord with the surprisingly inert nature of UO(2)(-). The results provide a basis to understand mechanisms of key reactions of uranium oxides with organics, and a foundation to extend DFT methodologies to more complex actinide systems which are not amenable to such direct experimental studies.
Inorganic Chemistry 03/2010; 49(8):3836-50. · 4.60 Impact Factor
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ABSTRACT: An assessment of the gas-phase energetics of neutral and singly and doubly charged cationic actinide monoxides and dioxides of thorium, protactinium, uranium, neptunium, plutonium, americium, and curium is presented. A consistent set of metal-oxygen bond dissociation enthalpies, ionization energies, and enthalpies of formation, including new or revised values, is proposed, mainly based on recent experimental data and on correlations with the electronic energetics of the atoms or cations and with condensed-phase thermochemistry.
The Journal of Physical Chemistry A 10/2009; 113(45):12599-606. · 2.95 Impact Factor
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ABSTRACT: Laser ablation of solid UO(3) or (NH(4))(2)U(2)O(7) yielded in the gas phase molecular uranium oxide anions with compositions ranging from [UO(n)](-) (n = 2-4) to [U(14)O(n)](-) (n = 32-35), as detected by Fourier transform ion cyclotron resonance mass spectrometry. The cluster series [U(x)O(3x)](-) for x < or = 6 and various [U(x)O(3x-y)](-), in which y increased with increasing x, could be identified. A few anions with H atoms were also present, and their abundance increased when hydrated UO(3) was used in place of anhydrous UO(3). Collision-induced dissociation experiments with some of the lower m/z cluster anions supported extended structures in which neutral UO(3) constitutes the building block. Cationic uranium oxide clusters [U(x)O(n)](+) (x = 2-9; n = 3-24) could also be produced and are briefly discussed. Common trends in the O/U ratios for both negative and positive clusters could be unveiled.
Inorganic Chemistry 05/2009; 48(12):5055-7. · 4.60 Impact Factor
