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  • 1
    Electronic Resource
    Electronic Resource
    Relativistic Effects on Bonding in Cationic Transition-Metal-Carbene Complexes: A Density-Functional Study (1995)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 117 (1995), S. 495-500 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00106a057
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  • 2
    Electronic Resource
    Electronic Resource
    Gas-Phase Ion Chemistry of Dimethyl Peroxide with the Bare Transition-Metal Cations Cr+, Mn+, Fe+, and Co+ (1995)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 117 (1995), S. 7711-7718 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00134a015
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  • 3
    Electronic Resource
    Electronic Resource
    Structure/Reactivity Relationships in the Unimolecular Gas-Phase Chemistry of Dialkyl Peroxide/Fe+ Complexes (1995)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 117 (1995), S. 12235-12242 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00154a025
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  • 4
    Electronic Resource
    Electronic Resource
    Relativistic coupled cluster calculations for neutral and singly charged Au3 clusters (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 9356-9362 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Relativistic coupled cluster studies are performed for the structures, dissociation energies, ionization potentials and electron affinities for Au, Au2 and Au3. The calculations show that the upward shifts of the ionization potentials and electron affinities of Aun clusters by approximately 2 eV compared to Cun or Agn base on relativistic effects. Au3+ is predicted to adopt a trigonal planar structure (D3h, 1A1), Au3 a E⊗ε Jahn–Teller distorted structure (C2v,2A1) 0.1 eV below the linear 2Σu+ arrangement, and Au3− adopts a linear structure (1Σg+). © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.481556
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  • 5
    Electronic Resource
    Electronic Resource
    The potential energy curve and dipole polarizability tensor of mercury dimer (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 115 (2001), S. 7401-7412 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Scalar relativistic coupled cluster calculations for the potential energy curve and the distance dependence of the static dipole polarizability tensor of Hg2 are presented and compared with current experimental work. The role of the basis set superposition error for the potential energy curve and the dipole polarizability is discussed in detail. Our recently optimized correlation consistent valence basis sets together with energy adjusted pseudopotentials are well suited to accurately describe the van der Waals system Hg2. The vibrational–rotational analysis of the best spin–orbit corrected potential energy curve yields re=3.74 Å, D0=328 cm−1, ωe=18.4 cm−1, and ωexe=0.28 cm−1 in reasonable agreement with experimental data (re=3.69±0.01 Å, De=380±25 cm−1, ωe=19.6±0.3 cm−1 and ωexe=0.25±0.05 cm−1). We finally present a scaled potential energy curve of the form ∑ja2jr−2j which fits the experimental fundamental vibrational transition of 19.1 cm−1 and the form of our calculated potential energy curve best (re=3.69 Å, D0=365 cm−1, ωe=19.7 cm−1, and ωexe=0.29 cm−1). We recommend these accurate two-body potentials as the starting point for the construction of many-body potentials in dynamic simulations of mercury clusters. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1402163
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  • 6
    Electronic Resource
    Electronic Resource
    Relativistic effects in gold chemistry. VI. Coupled cluster calculations for the isoelectronic series AuPt−, Au2, and AuHg+ (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 9457-9462 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Nonrelativistic and scalar relativistic pseudopotential calculations were carried out for the isoelectronic series of diatomic molecules AuPt−, Au2, and AuHg+ at the Hartree–Fock, second-order Møller–Plesset (MP2), and coupled-cluster [CCSD(T)] level. For Au2 we performed large scale fully relativistic Dirac–Hartree–Fock and MP2 benchmark calculations in order to test the reliability of the pseudopotential approximation. Both methods yield almost identical spectroscopic properties for Au2. The comparison further reveals that pseudopotentials correctly describe the effects of relativity on the spectroscopic properties of Au2. The yet unknown diatomic species AuPt− and AuHg+ are stable compounds, and their rotational–vibrational constants are predicted. These show striking similarities compared to the values of Au2. MP2 results including a set of three g-functions per metal atom indicate that higher angular momentum functions are important for accurately predicting the bond distance of these molecules. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478911
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  • 7
    Electronic Resource
    Electronic Resource
    Dimethyl Peroxide Radical Cation: A New Theoretical and Experimental Approach to the C2H6O•+2 Potential Energy Surface (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 626-638 
    Details
    ISSN: 0947-6539
    Keywords: ab initio calculations ; dimethyl peroxide ; mass spectrometry ; peroxides ; radical ions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure and the unimolecular fragmentations of the metastable dimethyl peroxide radical cation have been investigated by mass spectrometric and isotopic labeling methods as well as high-level ab initio calculations. In line with the theoretical results, neutralization-reionization and charge reversal experiments suggest that ionized dimethyl peroxide bears a CH3OOCH•3 connectivity. In the cation the O-O bond dissociation energy is larger than that of the neutral counterpart; in contrast, the C-O bond strength is slightly and that of the C-H bond significantly reduced upon ionization. These energetic changes upon one-electron oxidation of CH3OOCH3 are also reflected in the NR and CR mass spectra of CH3OOCH•+3. Further, for metastable CH3OOCH•3 two major fragmentation pathways are observed: 1) Loss of a hydrogen atom by cleavage of a C-H bond is associated with a skeletal reorganization, which gives rise to a proton-bound formaldehyde dimer. 2) The expulsion of a CH3O• radical leads to protonated formaldehyde in a surprisingly specific double hydrogen transfer involving a [CH3OH/CH2O]• ion/dipole complex as central intermediate; this complex also accounts for other minor fragmentation channels. The structures of intermediates and transition states are calculated with the BECKE 3LYP density-functional method employing a 6-311++G** basis.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030420
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  • 8
    Electronic Resource
    Electronic Resource
    A Comparative Study of Oxo-Ligand Effects in the Gas-Phase Chemistry of Atomic Lanthanide and Actinide Cations (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 1083-1090 
    Details
    ISSN: 0947-6539
    Keywords: actinides ; C-H activation ; lanthanides ; mass spectrometry ; metal oxides ; oxygen transfer ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effects of oxo ligands on lanthanide and actinide cations have been examined for the mono- and dioxocations MO+ and MO+2 of cerium, neodymium, thorium, and uranium by probing C-H and C-C bond activation of hydrocarbons in an FT-ICR mass spectrometer. The metal monoxide cations are readily available by reaction of the “bare” metal cations with O2, CO2, N2O, or H2O. In the ensuing oxidation of MO+, UO+2 is obtained by each of these oxidants, while CeO+ could only be oxidized by N2O. NO2 was necessary for the generation of ThO+2, and NdO+2 could not be prepared at all. The monoxides are rather unreactive and only dehydrogenate reactive substrates such as 1-butene and 1,4-cyclohexadiene to generate the corresponding butadiene or benzene complexes. In contrast, CeO+2 and ThO+2 react efficiently with different substrates by abstraction of a hydrogen atom and formation of the closed-shell species OMOH+, or by oxygen atom transfer to unsaturated hydrocarbons. In marked contrast, UO+2 only undergoes very slow adduct formation with unsaturated hydrocarbons. The results are compared with the reactions of the “bare” metals with respect to the influence of the oxo ligand as well as to the underlying electronic features of the investigated complexes.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030716
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  • 9
    Electronic Resource
    Electronic Resource
    Bimolecular Gas-Phase Reactions of d-Block Transition-Metal Cations With Dimethyl Peroxide: Trends Across the Periodic Table (1995)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 1 (1995), S. 608-613 
    Details
    ISSN: 0947-6539
    Keywords: gas-phase chemistry ; mass spectrometry ; periodic trends ; peroxides ; transition-metal ions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bimolecular gas-phase reactions of d-block transition-metal cations M+ with dimethyl peroxide were screened by means of Fourier transform ion cyclotron resonance mass spectrometry. The rich chemistry can be classified into four types of reactions: i) Oxygen-atom transfer to generate MO+, ii) elimination of radicals, mostly CH3O·, iii) intramolecular redox reaction of dimethyl peroxide to form CH3OH, CH2O and CO, and iv) charge transfer from the metal cation to produce CH3OOCH3+. Some general trends became apparent from this study. For example, the “early” transition metals almost exclusively induce oxygen transfer to generate MO+, in line with the notoriously high oxophilicities of these metals, and electron transfer is only observed for Zn+ and Hg+. Both the radical loss and the disproportionation reaction emerge from a rovibrationally highly excited insertion intermediate (CH3O)2M+, and for the first-row metals the branching ratio of the competing processes seems to be affected by the M+—OR bond strengths as well as the electronic groundstate configurations of M+. For the 4d and 5d cations Ru+—Ag+ and Pt+—Au+, respectively, products resulting from intramolecular redox reactions dominate; this probably reflects the higher propensity of these metal ions to facilitate β-hydrogen atom shifts.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19950010907
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  • 10
    Electronic Resource
    Electronic Resource
    Gas-Phase Reactions of Aliphatic Alcohols with ‘Bare’ FeO+ (1996)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 79 (1996), S. 123-132 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ion/molecule reactions of ‘bare’ FeO+ with linear and branched aliphatic alcohols have been examined by Fourier-transform ion-cyclotron resonance mass spectrometry. Depending on the chain length of the alcohol, three different types of reactions can be distinguished: (i) Oxidation of the alcohols in the α-positions, to yield the corresponding carbonyl-Fe+ complexes, involves an initial O—H bond activation of the alcohol resulting in the formation of RO—Fe+—OH as the central intermediate. (ii) The formation of Fe(OH)2+, concomitant by loss of the corresponding neutral alkenes, competes with the generation of neutral OFeOH and a carbocation R+. These couples point to the existence of an intracomplex acid-base equilibrium and are connected with each other by a proton transfer from either acid to the other, e.g. i-C3H7+ + OFeOH⇄C3H6 + Fe(OH)2+. The process is driven by the Lewis acidity of FeO+ and starts with the abstraction of a hydroxide anion from the alcohol. (iii) For longer alcohols, e.g. pentanol, functionalization of non-activated C—H bonds which are remote from the O functionality is observed. Here, the OH group of the alcohol serves as an anchor, which directs the reactive metal-oxide cation toward a particular site of the hydrocarbon chain.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19960790113
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