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  • 1
    Online Resource
    Online Resource
    Berlin, Heidelberg :Springer Berlin / Heidelberg,
    Keywords: Chemical bonds-Handbooks, manuals, etc. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (206 pages)
    Edition: 1st ed.
    ISBN: 9783540697077
    Series Statement: Topics in Organometallic Chemistry Series ; v.4
    Language: English
    Note: Intro -- Organometallic Bonding and Reactivity -- Volume Editors -- Editorial Board -- Preface -- Contents -- Gas-Phase Organometallic Chemistry -- Introduction -- Experimental Methods -- Atomic Metal and Metal Complex Ion Sources -- Electron Ionization -- Laser Vaporization and Glow Discharge -- Surface Ionization -- Multiphoton Ionization -- High-Pressure Sources -- Mass Spectrometric Methods -- ICR Mass Spectrometry -- Ion Beam Mass Spectrometry -- Thermochemistry of Metal-Carbon Bonds -- Methods of Analysis -- Reactions -- Data Analysis -- Covalent Metal-Carbon Bonds -- Cations -- Bis-Ligated Cations -- Neutrals -- Dative Metal-Carbon Bonds -- Ethene -- Benzene -- Alkanes -- Mechanisms for Alkane Activation -- Methane -- Early First Row Transition Metal Ions -- Late First Row Transition Metal Ions -- Second and Third Row Transition Metal Ions -- Ethane -- Propane -- Late First Row Transition Metal Ions -- Early First and Second Row Transition Metal Ions -- Effect of Ancillary Ligands -- Effect of an Oxo Ligand -- Reaction of CoO+ with Methane -- Reaction of FeO+ with Methane -- Reaction of Other Transition Metal Oxide Cations with Methane -- Conclusions -- References -- Static and Dynamic Structures of Organometallic Molecules and Crystals -- Introduction -- Static and Dynamic Structures of Organometallic Molecules in the Solid State -- Single Crystal X-ray Diffraction: Some Limitations -- Dynamical Processes at Molecular Level -- The Timescale in Diffraction Experiments -- Atomic Displacements -- Empirical Estimate of Reorientational Barriers -- Organometallic Crystal Isomerization, Phase Transitions and Polymorphism -- Crystal Polymorphism -- Crystals Formed by Structural Isomers -- Pseudo-Polymorphism of Electronic Isomers -- Pseudo-Polymorphism Arising from Disorder -- Crystal Transformations and Dynamics. , Perspectives of an Organometallic Solid State and Materials Chemistry -- References -- Theoretical Treatment of Organometallic Reaction Mechanisms and Catalysis -- Introduction -- Methods -- Qualitative Molecular Orbital Theory -- Nonempirical Methods -- Standard Ab Initio Methods -- Density Functional Theory Methods -- QM/MM Methods -- QM/MD Methods -- Selected Examples -- Olefin Polymerization Using Metallocene-Based Transition-Metal Catalysts -- Olefin Polymerization Using Late Transition-Metal Complexes as Catalysts -- Olefin Hydroformylation and the Wacker Process: Influence of the Solvent Effects -- Conclusion and Perspectives -- References -- A Critical Assessment of Density Functional Theory with Regard to Applications in Organometallic Chemistry -- Introduction -- Significant Problems and the Historical Role of Density Functional Theory -- Perspectives and Priorities -- Basics of Density Functional Theory - A Descriptive Presentation -- Density Functional Theory of Closed-Shell Systems: Non-Spin-Polarized Theory -- Density Functionals and Model Wave Functions -- The Kohn-Sham Procedure -- Effective Potentials -- Kohn-Sham Eigenvalues -- Extension to Open-Shell Systems -- Spin Density Functional Theory -- Spatial Symmetry Aspects -- Physical Constraints on Functionals from Properties of Electron Holes -- Exchange and Correlation Holes -- Functionals -- Approximate Functionals -- Local and Gradient-Corrected Approximate Functionals -- Hybrid Approximate Functionals -- Selected Applications -- Calibration and Validation -- Organometallics - Broad View -- Organometallics - Case Study of Transition-Metal-Catalyzed Oxygen Transfer Reactions -- Olefin Dihydroxylation with OsO4/H2O2 -- Olefin Epoxidation with CH3ReO3/H2O2 -- Acknowlgements -- References -- Hybrid Quantum Mechanics/Molecular Mechanics Methods in Transition Metal Chemistry. , Introduction -- Hybrid QM/MM Methods -- General Overview -- One-Step QM/MM Methods: Combined MO+MM Method -- Multistep QM/MM Methods: The IMOMM Method -- Checklist of Technical Features -- Applications -- Structural Studies -- Olefin Polymerization Via Homogeneous Catalysis -- Asymmetric Dihydroxylation of Olefins -- Agostic Complexes -- Bioinorganic Complexes -- Conclusions and Future Perspectives -- Acknowledgement -- References -- Author index Volumes 1-4.
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  • 2
    Online Resource
    Online Resource
    Berlin, Heidelberg :Springer Berlin / Heidelberg,
    Keywords: Organic compounds-Synthesis. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (321 pages)
    Edition: 1st ed.
    ISBN: 9783642731969
    DDC: 547.050459
    Language: English
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  • 3
    Keywords: Forschungsbericht
    Type of Medium: Online Resource
    Pages: 18 p. = 197 Kb, text and images , graphics
    Edition: [Elektronische Ressource]
    Language: German
    Note: Contract BMBF 03 D 0050 A7 , Differences between the printed and electronic version of the document are possible , Systemvoraussetzungen: Acrobat Reader.
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  • 4
    Keywords: Forschungsbericht ; Augenfolgebewegung ; Blickregistrierung
    Type of Medium: Online Resource
    Pages: Online-Ressource (11 S., 434 KB) , Ill.
    Edition: Ausg. 1
    Language: German
    Note: Förderkennzeichen BMBF 50 WP0408 , Unterschiede zwischen dem gedruckten Dokument und der elektronischen Ressource können nicht ausgeschlossen werden , Auch als gedr. Ausg. vorhanden , Systemvoraussetzungen: Acrobat reader.
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  • 5
    In: Earth and planetary science letters, Amsterdam [u.a.] : Elsevier, 1966, 274(2008), 1/2, Seite 1-13, 1385-013X
    In: volume:274
    In: year:2008
    In: number:1/2
    In: pages:1-13
    Description / Table of Contents: Regional climate modelling for the Late Cretaceous greenhouse and high-resolution marine stratigraphic records from both sides of the low latitude Atlantic show that tropical South American and African hydrology and watersheds had a strong effect on freshwater transfer into the Equatorial Atlantic and subsequently the marine carbon record. This conclusion is derived from new detailed geochemical records from Demerara Rise off Suriname drilled at Ocean Drilling Program (ODP) Site 1261 combined with frequency analyses and climate simulations providing evidence for mainly eccentricity-driven changes in carbon burial in the western tropical Atlantic. Shorter orbital frequencies, in particular precession, clearly dominating black shale cycles off tropical Africa (ODP Site 959), are far less dominant at Demerara Rise despite comparable time resolution of the geochemical records. We suggest that these different frequency patterns in carbon burial were related to the regional evolution of Cretaceous watersheds and hydrology in tropical South America and Africa. River discharge deduced from simulations indicates higher and less variable discharge from South America compared to western Africa at that time. This runoff pattern would have supported more permanent anoxic conditions off South America compared to Africa, at least indirectly, and caused the lack of strong higher frequency geochemical cycles in the western sector of the Equatorial Atlantic. Furthermore, climate simulations show a general switch of primary runoff from either side of the Cretaceous Equatorial Atlantic every half precession cycle (i.e. every ~ 10 kyr). Similarities between the developments of Cretaceous and Holocene hydrology in the tropical Atlantic area imply that orbital-scale evolution of watersheds is a robust feature through time that is independent from the mean global climate state. Based upon the comparison of Cretaceous and Holocene trends in hydrology we infer that future hydrology in the study region may develop in a comparable direction to the one observed in the Cretaceous. If true, this suggests that the modern Amazon rain forest could shrink over the next millennium due to a ~ 30% loss of moisture while the Congo rain forest in Africa is likely to expand in response to a 14% gain in moisture.
    Type of Medium: Online Resource
    Pages: graph. Darst
    ISSN: 1385-013X
    Language: English
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  • 6
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 6557-6557 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 615-627 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The vibrational overtone spectra of the acetylenic and methyl C–H stretches of propyne were obtained for the v=1 to v=6 and v=1 to v=7 levels, respectively. Propyne-dl was also studied and the methyl C–H stretching overtones were measured from v=1 to the v=7 level. The C–D stretch was observed only in the fundamental and first overtone regions. Lower level overtones were obtained by standard infrared techniques, while higher absorptions (〉12 000 cm−1) were obtained by intracavity dye laser photoacoustic spectroscopy. The C–H stretches in both molecules were analyzed in terms of the local-mode model, and harmonic frequencies (ωi) and anharmonicities (Xii) were calculated. In propyne these values were (acetylenic C–H stretch) ω1=3384±5 cm−1 and X11=−50±1 cm−1 and (methyl C–H stretch) ωm =3037±5 cm−1 and Xmm =−65±2 cm−1. In propyne-dl the methyl C–H stretch parameters were ωm =3034±5 cm−1 and Xmm =−64±2 cm−1. For propyne, a hot band (ν9→ν9+vν1) accompanying the acetylenic C–H stretch was observed for v=1–6 and the anharmonic interaction constant (X19=−23±7 cm−1) was calculated. A crossover from normal- to local-mode behavior has been observed for the methyl C–H stretches in propyne and propyne-dl at the v=3 and 4 levels. Below v=3 the symmetric and antisymmetric methyl C–H stretches are designated by the usual normal-mode notation (ν2 and ν6 in propyne; ν1 and ν6 in propyne-dl), while for v≥3 the single observed band is designated as a "methyl'' C–H stretch, vνm. Peak absorption cross sections have been measured for Δv1=1–5, Δvm =3–5, Δv2=1 and 2, and the parallel component of 2ν6 in propyne, and for Δv2=1 and 2, Δv1=1 and 2, Δvm =3 and 4, and the parallel component of 2ν6 in propyne-dl. During the course of this work the spectral constants of 3,3,3-trifluoropropyne were redetermined. The harmonic frequency ω1 is 3376±6 cm−1, the anharmonicityX11 is −49±1 cm−1, and the anharmonic interaction constant X17 is −17±6 cm−1.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Inorganic chemistry 24 (1985), S. 4020-4023 
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 7434-7447 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A study has been made of the vibrational energy flow mechanisms and time scales pertaining to the overtone stretch excitations of methyl and acetylenic CH stretches in propyne. Classical trajectories are used to interpret the experimental data for the overtone linewidths, as well as to analyze the role that individual modes play in determining energy flow. The full anharmonic potential surface for these calculations, including all modes, has been developed from spectroscopic and structural information, including the linewidth data. The principal results are: (1) The trajectory calculations show a localization transition, corresponding to a switch over from normal-mode behavior for CH3 excitations up to v≅3 to a local-mode CH excitation within the CH3 moiety for excitations of v(approximately-greater-than)6, with transition behavior for v=4,5. (2) The acetylenic CH shows local-mode behavior from v=1. Extremely long lifetimes are found for the excitations of this mode, and the trajectories indicate that the experimental width is predominantly rotational. (3) The rocking and deformation modes are dominant receiving modes in the relaxation of the methyl stretch. (4) A shorter lifetime is calculated for the v=6 vs the v=5 or v=7 overtones of the methyl C–H stretch. Experimental results are qualitatively consistent with this prediction. The origin of this shorter lifetime is a band of resonances between the stretch excitation and combinations of rocking, deformation, and pseudorotation modes. (5) CH3 internal rotation figures importantly in the relaxation of some levels (v=5, 8 of CH3) where it "closes the energy gap'' for achieving resonant energy transfer. (6) For v=8 of the methyl CH, some direct energy transfer to both C–C(Triple Bond)C stretching modes is seen. The switching on of the stretches as receiving modes is a consequence of sufficiently strong interactions between the excited H and the C–C(Triple Bond)C chain, which take place at these high vibrational energies. (7) Evidence is found for long distance "through-space'' energy transfer due to long-range dipole–dipole forces. This transfer occurs from the acetylenic to the methyl CH stretches. This result is illustrated for the v=2 excitation of the acetylenichydrogen, and constitutes a direct demonstration of intramolecular long-distance, through-space v–v energy transfer. These results demonstrate the potential importance of large amplitude modes such as rocking and deformation as initial receiving modes for vibrational energy from excited CH overtones. On the time scale probed here (∼1 ps), despite the availability of many degrees of freedom, the transfer process is dominated by specific energy transfer channels and by the specific behavior of individual modes, rather than by statistical considerations, which will certainly prevail on longer time scales.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Haemophilia 3 (1997), S. 0 
    ISSN: 1365-2516
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The in vitro stability of porcine factor VIII (PF VIII) was evaluated when it was reconstituted with sterile water (PF VIIISW) to ≈ 30 U PFVIII mL−1, as per the manufacturer’s recommendations, and stored in plastic syringes at room temperature, with and without heparin and at four different dilutions. PF VIII was prepared antiseptically without laminar airflow and remained sterile at room temperature for 1 week. PF VIIISW retained at least 88% of baseline activity for 48 h and 74–86% for 72 h. Addition of heparin 1 unit mL−1 solution resulted in a decrease in the stability of PF VIIISW to 72–74 % of baseline values by 24 h. Reconstituted PF VIIISW, further diluted with normal saline to 10–24 U PF VIII mL−1, retained 〈inlineGraphic alt="geqslant R: gt-or-equal, slanted" extraInfo="nonStandardEntity" href="urn:x-wiley:13518216:HAE114:ges" location="ges.gif"/〉 98% of baseline activity for 48 h and 〈inlineGraphic alt="geqslant R: gt-or-equal, slanted" extraInfo="nonStandardEntity" href="urn:x-wiley:13518216:HAE114:ges" location="ges.gif"/〉 84% of baseline for 72 h. PF VIII diluted to 6 U mL−1, however, retained 100% baseline activity for only 24 h, and declined to 71% and 64 % of baseline by 48 and 72 h, respectively. PF VIII reconstituted with normal saline, instead of sterile water, retained 90% or more of baseline activity for a minimum of 4 days. Once reconstituted, PF VIII appeared to be more stable at room temperature than when stored in the refrigerator.These in vitro stability studies confirm that PF VIII (30 U mL−1) can be given effectively by prolonged continuous infusion, since it retains 〈inlineGraphic alt="geqslant R: gt-or-equal, slanted" extraInfo="nonStandardEntity" href="urn:x-wiley:13518216:HAE114:ges" location="ges.gif"/〉 88% baseline activity at room temperature in a plastic syringe for a minimum of 48 h, remains sterile and will maintain baseline PF VIII levels when further diluted with saline.
    Type of Medium: Electronic Resource
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