51
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Wren SW, Vogelhuber KM, Garver JM, Kato S, Sheps L, Bierbaum VM, Lineberger WC. C–H Bond Strengths and Acidities in Aromatic Systems: Effects of Nitrogen Incorporation in Mono-, Di-, and Triazines. J Am Chem Soc 2012; 134:6584-95. [DOI: 10.1021/ja209566q] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Scott W. Wren
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - Kristen M. Vogelhuber
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - John M. Garver
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - Shuji Kato
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - Leonid Sheps
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - Veronica M. Bierbaum
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - W. Carl Lineberger
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
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52
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Gong Y, Andrews L, Chen M, Dixon DA. Reactions of Late Lanthanide Metal Atoms and Methanol in Solid Argon: A Matrix Isolation Infrared Spectroscopic and Theoretical Study. J Phys Chem A 2011; 115:14581-92. [DOI: 10.1021/jp209135a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yu Gong
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, United States
| | - Lester Andrews
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, United States
| | - Mingyang Chen
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487-0336, United States
| | - David A. Dixon
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487-0336, United States
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53
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Ge Y, Cameron Shore T. Theoretical calculations on the hydrogen elimination of ethene with chemical accuracy. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.09.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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54
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Kopyra J, König-Lehmann C, Illenberger E. Low energy (0–10 eV) electron driven reactions in the halogenated organic acids CCl3COOH, CClF2COOH, and CF3CHNH2COOH (trifluoroalanine). J Chem Phys 2011; 135:124307. [DOI: 10.1063/1.3641479] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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55
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Chen K, Wang ZC, Schlangen M, Wu YD, Zhang X, Schwarz H. Thermal Activation of Methane and Ethene by Bare MO.+ (M=Ge, Sn, and Pb): A Combined Theoretical/Experimental Study. Chemistry 2011; 17:9619-25. [DOI: 10.1002/chem.201101538] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Indexed: 11/10/2022]
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Abstract
The topic of ambient gas analysis has been rapidly developed in the last few years with the evolution of the exciting new techniques such as DESI, DART and EESI. The essential feature of all is that analysis of trace gases can be accomplished either in the gas phase or those released from surfaces, crucially avoiding sample collection or modification. In this regard, selected ion flow tube mass spectrometry, SIFT-MS, also performs ambient analyses both accurately and rapidly. In this focused review we describe the underlying ion chemistry underpinning SIFT-MS through a discourse on the reactions of different classes of organic and inorganic molecules with H(3)O(+), NO(+) and O(2)(+)˙ studied using the SIFT technique. Rate coefficients and ion products of these reactions facilitate absolute SIFT-MS analyses and can also be useful for the interpretation of data obtained by the other ambient analysis methods mentioned above. The essential physics and flow dynamics of SIFT-MS are described that, together with the reaction kinetics, allow SIFT-MS to perform absolute ambient analyses of trace compounds in humid atmospheric air, exhaled breath and the headspace of aqueous liquids. Several areas of research that, through pilot experiments, are seen to benefit from ambient gas analysis using SIFT-MS are briefly reviewed. Special attention is given to exhaled breath and urine headspace analysis directed towards clinical diagnosis and therapeutic monitoring, and some other areas researched using SIFT-MS are summarised. Finally, extensions to current areas of application and indications of other directions in which SIFT-MS can be exploited for ambient analysis are alluded to.
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Affiliation(s)
- David Smith
- Institute for Science and Technology in Medicine, School of Medicine, Keele University, Hartshill, Stoke-on-Trent, UK
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57
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El-Nahas AM, Mangood AH, Takeuchi H, Taketsugu T. Thermal Decomposition of 2-Butanol as a Potential Nonfossil Fuel: A Computational Study. J Phys Chem A 2011; 115:2837-46. [DOI: 10.1021/jp110628k] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ahmed M El-Nahas
- Chemistry Department, Faculty of Science, El-Menoufia University, Shebin El-Kom, Egypt
| | - Ahmed H. Mangood
- Chemistry Department, Faculty of Science, El-Menoufia University, Shebin El-Kom, Egypt
| | - Hikaru Takeuchi
- Department of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Tetsuya Taketsugu
- Department of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
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58
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Zhu RS, Lin MC. Ab initio chemical kinetic study on the reactions of ClO with C2H2 and C2H4. J Phys Chem A 2010; 114:13395-401. [PMID: 21128616 DOI: 10.1021/jp107596y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mechanisms for the reactions of ClO with C(2)H(2) and C(2)H(4) have been investigated at the CCSD(T)/CBS level of theory. The results show that in both systems, the interaction between the Cl atom of the ClO radical and the triple and double bonds of C(2)H(2) and C(2)H(4) forms prereaction van der Waals complexes with the O-Cl bond pointing perpendicularly toward the π-bonds, both with 2.1 kcal/mol binding energies. The mechanism is similar to those of the HO-C(2)H(2)/C(2)H(4) systems. The rate constants for the low energy channels have been predicted by statistical theory. For the reaction of ClO and C(2)H(2), the main channels are the production of CH(2)CO + Cl (k(1a)) and CHCO + HCl (k(1b)), with k(1a) = 1.19 × 10(-15)T(1.18) exp(-5814/T) and k(1b) = 6.94 × 10(-21) × T(2.60) exp(-6587/T) cm(3) molecule(-1) s(-1). For the ClO + C(2)H(4) reaction, the main pathway leads to C(2)H(4)O + Cl (k(2a)) with the predicted rate constant k(2a) = 2.13 × 10(-17)T(1.52) exp(-3849/T) in the temperature range of 300-3000 K. These rate constants are pressure-independent below 100 atm.
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Affiliation(s)
- R S Zhu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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59
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Joseph S, Varandas AJC. Accurate MRCI and CC Study of the Most Relevant Stationary Points and Other Topographical Attributes for the Ground-State C2H2 Potential Energy Surface. J Phys Chem A 2010; 114:13277-87. [DOI: 10.1021/jp109830s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. Joseph
- Departamento de Química, Universidade de Coimbra 3004-535 Coimbra, Portugal
| | - A. J. C. Varandas
- Departamento de Química, Universidade de Coimbra 3004-535 Coimbra, Portugal
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60
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Rayne S, Forest K. Gas phase acidities and associated equilibrium isotope effects for selected main group mono- and polyhydrides, carbon acids, and oxyacids: A G4 and W1BD study. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.theochem.2010.06.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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61
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Cabeza JA, Pérez-Carreño E. The Bridging Acetylene to Bridging Vinylidene Rearrangement in a Triruthenium Carbonyl Cluster: A DFT Mechanistic Study. Organometallics 2010. [DOI: 10.1021/om100607e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Javier A. Cabeza
- Departamento de Química Orgánica e Inorgánica-IUQOEM, Universidad de Oviedo-CSIC, E-33071 Oviedo, Spain
| | - Enrique Pérez-Carreño
- Departamento de Química Física y Analítica, Universidad de Oviedo, E-33071 Oviedo, Spain
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62
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Hanf A, Volpp HR, Sharma P, Mittal JP, Vatsa RK. Ultraviolet photochemistry of buta-1,3- and buta-1,2-dienes: Laser spectroscopic absolute hydrogen atom quantum yield and translational energy distribution measurements. J Chem Phys 2010; 133:024308. [DOI: 10.1063/1.3462951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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63
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Villano SM, Eyet N, Wren SW, Ellison GB, Bierbaum VM, Lineberger WC. Photoelectron spectroscopy and thermochemistry of the peroxyformate anion. J Phys Chem A 2010; 114:191-200. [PMID: 19827803 DOI: 10.1021/jp907569w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The 351.1 nm photoelectron spectrum of the peroxyformate anion has been measured. The photoelectron spectrum displays vibronic features in both the 2A'' ground and 2A' first excited states of the corresponding radical. Franck-Condon simulations of the spectrum show that the ion is formed exclusively in the trans-conformation. The electron affinity (EA) of the peroxyformyl radical was determined to be 2.493 +/- 0.006 eV, while the term energy splitting was found to be 0.783-0.020+0.060 eV. Extended progressions in the C-OO (973 +/- 20 cm-1) and O-O (1098 +/- 20 cm-1) stretching modes are observed in the ground state of the radical. The fundamental frequency of the in-plane OCO bend was found to be 574 +/- 35 cm-1. The gas-phase acidity of peroxyformic acid has been determined using an ion-molecule bracketing technique. On the basis of the size of the trans- to cis- isomerization barrier, the measured acidity was assigned to the higher energy trans-conformer of the acid. The gas-phase acidity of the lower energy cis-conformer of peroxyformic acid was found from the measured acidity for the trans-form and a calculated energy correction: DeltaaG298(cis-peroxyformic acid) = 346.8 +/- 3.3 kcal mol-1 and DeltaaH298(cis-peroxyformic acid) = 354.4 +/- 3.3 kcal mol-1. Using a negative ion EA/acidity thermochemical cycle, the O-H bond dissociation energy (D0) values of the trans- and cis-conformers of peroxyformic acid to form the trans-radical were determined to be 94.0 +/- 3.3 and 97.1 +/- 3.3 kcal mol-1, respectively. The heat of formation (DeltafH298) of the trans-peroxyformyl radical was found to be -22.8 +/- 3.5 kcal mol-1.
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Affiliation(s)
- Stephanie M Villano
- JILA, University of Colorado and the National Institute of Standards and Technology and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, USA
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64
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Joseph S, Varandas AJC. Ab initio Based DMBE Potential Energy Surface for the Ground Electronic State of the C2H Molecule. J Phys Chem A 2010; 114:2655-64. [DOI: 10.1021/jp910269w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. Joseph
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - A. J. C. Varandas
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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65
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Chapter 7 Pyrolysis of Hydrocarbons. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s0167-9244(09)02807-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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66
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Villano SM, Eyet N, Wren SW, Ellison GB, Bierbaum VM, Lineberger WC. Photoelectron spectroscopy and thermochemistry of the peroxyacetate anion. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2010; 16:255-268. [PMID: 20530835 DOI: 10.1255/ejms.1055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The 351.1 nm photoelectron spectrum of the peroxyacetate anion, (CH(3)C(O)OO(-)) was measured. Analysis of the spectrum shows that the observed spectral features arise almost exclusively from transitions between the trans-conformer of the anion and the X(2)A'' and A (2)A' states of the corresponding radical. The electron affinity of trans-CH(3)C(O)OO is 2.381+/- 0.007 eV and the term energy splitting of the A (2)A' state is 0.691 +/- 0.009 eV, in excellent agreement with two prior values [Zalyubovsky et al. J. Phys. Chem. A 107, 7704 (2003); Hu et al. J. Phys. Chem. 124, 114305/1 (2006); Hu et al. J. Phys. Chem. 110, 2629 (2006)]. The gas-phase acidity of trans-peroxyacetic acid was bracketed between the acidity of acetic acid and tert-butylthiol at Delta(a)G(298)(trans-CH(3)C(O)OOH)=1439 +/- 14 kJ mol(-1) and Delta(a)H(298)(trans-CH(3)C(O)OOH)=1467+/-14 kJ mol(-1). The acidity of cis-CH(3)C(O)OOH was found by adding a calculated energy correction to the acidity of the trans-conformer; Delta(a)G(298)[cis-CH(3)C(O)OOH] = 1461 +/- 14 kJ mol(-1) and Delta(a)H(298)[cis- CH(3)C(O)OOH]=1490+/-14 kJ mol(-1). The O-H bond dissociation energies for both conformers were determined using a negative ion thermodynamic cycle to be D(0)[trans- CH(3)C(O)OOH]=381+/-14 kJ mol(-1) and D(0)[cis- CH(3)C(O)OOH]=403+/-14 kJ mol(-1). The atmospheric implications of these results and relations to the thermochemistry of peroxyacetyl nitrate are discussed briefly.
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Affiliation(s)
- Stephanie M Villano
- JILA, University of Colorado and the National Institute of Standards and Technology and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0440, USA
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67
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Kočišek J, Papp P, Mach P, Vasil’ev YV, Deinzer ML, Matejčík Š. Resonance Electron Capture by Serine. J Phys Chem A 2009; 114:1677-83. [DOI: 10.1021/jp906636b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Jaroslav Kočišek
- Department of Experimental Physics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Bratislava, Slovak Republic, Departmet of Nuclear Physics and Biophysics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Slovak Republic, Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-7302, and Department of Physics, Bashkir State Agricultural University, 450001, Ufa, Russia
| | - Peter Papp
- Department of Experimental Physics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Bratislava, Slovak Republic, Departmet of Nuclear Physics and Biophysics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Slovak Republic, Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-7302, and Department of Physics, Bashkir State Agricultural University, 450001, Ufa, Russia
| | - Pavel Mach
- Department of Experimental Physics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Bratislava, Slovak Republic, Departmet of Nuclear Physics and Biophysics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Slovak Republic, Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-7302, and Department of Physics, Bashkir State Agricultural University, 450001, Ufa, Russia
| | - Yury V. Vasil’ev
- Department of Experimental Physics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Bratislava, Slovak Republic, Departmet of Nuclear Physics and Biophysics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Slovak Republic, Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-7302, and Department of Physics, Bashkir State Agricultural University, 450001, Ufa, Russia
| | - Max L. Deinzer
- Department of Experimental Physics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Bratislava, Slovak Republic, Departmet of Nuclear Physics and Biophysics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Slovak Republic, Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-7302, and Department of Physics, Bashkir State Agricultural University, 450001, Ufa, Russia
| | - Štefan Matejčík
- Department of Experimental Physics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Bratislava, Slovak Republic, Departmet of Nuclear Physics and Biophysics, Comenius University Bratislava, Mlynská Dolina F2, 84248, Slovak Republic, Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-7302, and Department of Physics, Bashkir State Agricultural University, 450001, Ufa, Russia
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68
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Jochnowitz EB, Zhang X, Nimlos MR, Flowers BA, Stanton JF, Ellison GB. Infrared Spectrum of the Propargyl Peroxyl Radical, HC≡C—CH2OO X̃ 2A′′. J Phys Chem A 2009; 114:1498-507. [DOI: 10.1021/jp907806g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Evan B. Jochnowitz
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
| | - Xu Zhang
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
| | - Mark R. Nimlos
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
| | - Bradley A. Flowers
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
| | - John F. Stanton
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
| | - G. Barney Ellison
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
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69
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Creati F, Coletti C, Re N. Density Functional Study of Butadiyne to Butatrienylidene Isomerization in [Ru(HC≡CC≡CH)(PMe3)2(Cp)]+. Organometallics 2009. [DOI: 10.1021/om9007295] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Francesco Creati
- Dipartimento di Scienze del Farmaco, Università G. D'Annunzio, Via dei Vestini, 31, I-66100 Chieti, Italy
| | - Cecilia Coletti
- Dipartimento di Scienze del Farmaco, Università G. D'Annunzio, Via dei Vestini, 31, I-66100 Chieti, Italy
| | - Nazzareno Re
- Dipartimento di Scienze del Farmaco, Università G. D'Annunzio, Via dei Vestini, 31, I-66100 Chieti, Italy
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70
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BOGGIO-PASQUA M, VORONIN AI, HALVICK PH, RAYEZ JC, VARANDAS AJC. Coupled ab initio potential energy surfaces for the two lowest 2A′ electronic states of the C2H molecule. Mol Phys 2009. [DOI: 10.1080/00268970009483396] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- M. BOGGIO-PASQUA
- a Laboratoire de Physico-Chimie Moléculaire—UMR 5803/CNRS , Université Bordeaux 1 , 33405 , Talence Cedex, France
| | - A. I. VORONIN
- a Laboratoire de Physico-Chimie Moléculaire—UMR 5803/CNRS , Université Bordeaux 1 , 33405 , Talence Cedex, France
| | - PH. HALVICK
- a Laboratoire de Physico-Chimie Moléculaire—UMR 5803/CNRS , Université Bordeaux 1 , 33405 , Talence Cedex, France
| | - J.-C. RAYEZ
- a Laboratoire de Physico-Chimie Moléculaire—UMR 5803/CNRS , Université Bordeaux 1 , 33405 , Talence Cedex, France
| | - A. J. C. VARANDAS
- b Departamento de Química , Universidade de Coimbra , 3049 , Coimbra Codex , Portugal
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71
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Grant DJ, Matus MH, Anderson KD, Camaioni DM, Neufeldt SR, Lane CF, Dixon DA. Thermochemistry for the Dehydrogenation of Methyl-Substituted Ammonia Borane Compounds. J Phys Chem A 2009; 113:6121-32. [DOI: 10.1021/jp902196d] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Daniel J. Grant
- Chemistry Department, University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruzana, México, Fundamental Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, and Department of Chemistry and Biochemistry, Northern Arizona University, South Beaver Street, Building 20, Room 125, Flagstaff, Arizona 86011-5698
| | - Myrna H. Matus
- Chemistry Department, University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruzana, México, Fundamental Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, and Department of Chemistry and Biochemistry, Northern Arizona University, South Beaver Street, Building 20, Room 125, Flagstaff, Arizona 86011-5698
| | - Kevin D. Anderson
- Chemistry Department, University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruzana, México, Fundamental Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, and Department of Chemistry and Biochemistry, Northern Arizona University, South Beaver Street, Building 20, Room 125, Flagstaff, Arizona 86011-5698
| | - Donald M. Camaioni
- Chemistry Department, University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruzana, México, Fundamental Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, and Department of Chemistry and Biochemistry, Northern Arizona University, South Beaver Street, Building 20, Room 125, Flagstaff, Arizona 86011-5698
| | - Sharon R. Neufeldt
- Chemistry Department, University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruzana, México, Fundamental Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, and Department of Chemistry and Biochemistry, Northern Arizona University, South Beaver Street, Building 20, Room 125, Flagstaff, Arizona 86011-5698
| | - Clinton F. Lane
- Chemistry Department, University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruzana, México, Fundamental Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, and Department of Chemistry and Biochemistry, Northern Arizona University, South Beaver Street, Building 20, Room 125, Flagstaff, Arizona 86011-5698
| | - David A. Dixon
- Chemistry Department, University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, A. P. 575, Xalapa, Veracruzana, México, Fundamental Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, and Department of Chemistry and Biochemistry, Northern Arizona University, South Beaver Street, Building 20, Room 125, Flagstaff, Arizona 86011-5698
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72
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Cheng L, Wang J, Wang M, Wu Z. Theoretical studies on the reaction mechanism of oxidation of primary alcohols by Zn/Cu(ii)-phenoxyl radical catalyst. Dalton Trans 2009:3286-97. [DOI: 10.1039/b817985a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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73
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Domin D, Braïda B, Lester Jr. WA. Breathing Orbital Valence Bond Method in Diffusion Monte Carlo: C−H Bond Dissociation of Acetylene. J Phys Chem A 2008; 112:8964-9. [DOI: 10.1021/jp8020062] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dominik Domin
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California at Berkeley, Berkeley, California 94720-1460, UPMC Université Paris 06, UMR 7616, Laboratoire de Chimie Théorique, Case courrier 137 4 place Jussieu, 75005, Paris, France, CNRS Centre National de la Recherche Scientifique, UMR 7616, 75252 Paris, France, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Benoît Braïda
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California at Berkeley, Berkeley, California 94720-1460, UPMC Université Paris 06, UMR 7616, Laboratoire de Chimie Théorique, Case courrier 137 4 place Jussieu, 75005, Paris, France, CNRS Centre National de la Recherche Scientifique, UMR 7616, 75252 Paris, France, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - William A. Lester Jr.
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California at Berkeley, Berkeley, California 94720-1460, UPMC Université Paris 06, UMR 7616, Laboratoire de Chimie Théorique, Case courrier 137 4 place Jussieu, 75005, Paris, France, CNRS Centre National de la Recherche Scientifique, UMR 7616, 75252 Paris, France, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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74
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75
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Landera A, Krishtal SP, Kislov VV, Mebel AM, Kaiser RI. Theoretical study of the C6H3 potential energy surface and rate constants and product branching ratios of the C2H(Σ+2)+C4H2(Σg+1) and C4H(Σ+2)+C2H2(Σg+1) reactions. J Chem Phys 2008; 128:214301. [DOI: 10.1063/1.2929821] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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76
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Matthíasson K, Wang H, Kvaran Á. (2+n) REMPI of acetylene: Gerade Rydberg states and photorupture channels. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.04.104] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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77
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Tuna T, Chabot M, Pino T, Désesquelles P, LePadellec A, Martinet G, Barat M, Lucas B, Mezdari F, Montagnon L, Van-Oanh NT, Lavergne L, Lachaize A, Carpentier Y, Béroff K. Fragmentation branching ratios of highly excited hydrocarbon molecules CnH and their cations CnH+ (n⩽4). J Chem Phys 2008; 128:124312. [DOI: 10.1063/1.2884862] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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78
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Lu X, Xiang P, Wei R, Che X. Theoretical study on mechanism of cycloaddition reaction between dimethyl methylene carbene and ethylene. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.theochem.2007.12.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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79
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Abstract
Organic vinylidene species have found limited use in organic synthesis owing to their inaccessibility. In contrast, metal vinylidenes are much more stable and may be readily accessed through transition-metal activation of terminal alkynes. These electrophilic species may be trapped by a number of nucleophiles. Additionally, metal vinylidenes can participate in pericyclic reactions and processes that involve migration of a metal ligand to the vinylidene species. This Focus Review addresses the reactions and applications of metal vinylidenes in organic synthesis.
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Affiliation(s)
- Barry M Trost
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
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80
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Dong F, Roberts M, Nesbitt DJ. High-resolution infrared spectroscopy of jet-cooled vinyl radical: Symmetric CH2 stretch excitation and tunneling dynamics. J Chem Phys 2008; 128:044305. [DOI: 10.1063/1.2816704] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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81
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Shi Y, Ervin KM. Hydrogen Atom Transfer Reactions of C2-, C4-, and C6-: Bond Dissociation Energies of Linear H−C2n- and H−C2n (n = 1, 2, 3). J Phys Chem A 2008; 112:1261-7. [DOI: 10.1021/jp077181c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yang Shi
- Department of Chemistry and Chemical Physics Program, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557-0216
| | - Kent M. Ervin
- Department of Chemistry and Chemical Physics Program, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557-0216
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82
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83
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Nguyen MT, Matus MH, Lester, WA, Dixon DA. Heats of Formation of Triplet Ethylene, Ethylidene, and Acetylene. J Phys Chem A 2007; 112:2082-7. [DOI: 10.1021/jp074769a] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Minh Tho Nguyen
- Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0339, Department of Chemistry, University of Leuven, B-3001 Leuven, Belgium, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, and Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Myrna H. Matus
- Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0339, Department of Chemistry, University of Leuven, B-3001 Leuven, Belgium, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, and Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - William A. Lester,
- Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0339, Department of Chemistry, University of Leuven, B-3001 Leuven, Belgium, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, and Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - David A. Dixon
- Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0339, Department of Chemistry, University of Leuven, B-3001 Leuven, Belgium, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, and Department of Chemistry, University of California, Berkeley, California 94720-1460
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84
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Meloni G, Selby TM, Goulay F, Leone SR, Osborn DL, Taatjes CA. Photoionization of 1-Alkenylperoxy and Alkylperoxy Radicals and a General Rule for the Stability of Their Cations. J Am Chem Soc 2007; 129:14019-25. [DOI: 10.1021/ja075130n] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giovanni Meloni
- Contribution from the Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, Chemical Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Departments of Chemistry and Physics, University of California, Berkeley, California 94720
| | - Talitha M. Selby
- Contribution from the Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, Chemical Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Departments of Chemistry and Physics, University of California, Berkeley, California 94720
| | - Fabien Goulay
- Contribution from the Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, Chemical Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Departments of Chemistry and Physics, University of California, Berkeley, California 94720
| | - Stephen R. Leone
- Contribution from the Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, Chemical Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Departments of Chemistry and Physics, University of California, Berkeley, California 94720
| | - David L. Osborn
- Contribution from the Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, Chemical Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Departments of Chemistry and Physics, University of California, Berkeley, California 94720
| | - Craig A. Taatjes
- Contribution from the Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, Chemical Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Departments of Chemistry and Physics, University of California, Berkeley, California 94720
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85
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Armentrout PB. Activation of C2H6 and C3H8 by Gas-Phase Mo+: Thermochemistry of Mo−Ligand Complexes. Organometallics 2007. [DOI: 10.1021/om700579m] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- P. B. Armentrout
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112
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86
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Mauracher A, Denifl S, Aleem A, Wendt N, Zappa F, Cicman P, Probst M, Märk TD, Scheier P, Flosadóttir HD, Ingólfsson O, Illenberger E. Dissociative electron attachment to gas phase glycine: exploring the decomposition pathways by mass separation of isobaric fragment anions. Phys Chem Chem Phys 2007; 9:5680-5. [PMID: 17960256 DOI: 10.1039/b709140k] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dissociative electron attachment to gas phase glycine generates a number of fragment ions, among them ions observed at the mass numbers 15, 16 and 26 amu. From stoichiometry they can be assigned to the chemically rather different species NH(-)/CH(3)(-)(15 amu), O(-)/NH(2)(-)(16 amu) and CN(-)/C(2)H(2)(-)(26 amu). Here we use a high resolution double focusing two sector mass spectrometer to separate these isobaric ions. It is thereby possible to unravel the decomposition reactions of the different transient negative ions formed upon resonant electron attachment to neutral glycine in the energy range 0-15 eV. We find that within the isobaric ion pairs, the individual components generally arise from resonances located at substantial different energies. The corresponding unimolecular decompositions involve complex reaction sequences including multiple bond cleavages and substantial rearrangement in the precursor ion. To support the interpretation and assignments we also use (13)C labelling of glycine at the carboxylic group.
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Affiliation(s)
- A Mauracher
- Institut für Ionenphysik und Angewandte Physik, Leopold Franzens Universität Innsbruck and Center for Molecular Biosciences Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria.
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87
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Ismail H, Goldsmith CF, Abel PR, Howe PT, Fahr A, Halpern JB, Jusinski LE, Georgievskii Y, Taatjes CA, Green WH. Pressure and temperature dependence of the reaction of vinyl radical with ethylene. J Phys Chem A 2007; 111:6843-51. [PMID: 17569512 DOI: 10.1021/jp071041l] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This work reports measurements of absolute rate coefficients and Rice-Ramsperger-Kassel-Marcus (RRKM) master equation simulations of the C2H3+C2H4 reaction. Direct kinetic studies were performed over a temperature range of 300-700 K and pressures of 20 and 133 mbar. Vinyl radicals (H2C=CH) were generated by laser photolysis of vinyl iodide (C2H3I) at 266 nm, and time-resolved absorption spectroscopy was used to probe vinyl radicals through absorption at 423.2 nm. Measurements at 20 mbar are in good agreement with previous determinations at higher temperature. A weighted three-parameter Arrhenius fit to the experimental rate constant at 133 mbar, with the temperature exponent fixed, gives k=(7+/-1)x10(-14) cm3 molecule(-1) s(-1) (T/298 K)2 exp[-(1430+/-70) K/T]. RRKM master equation simulations, based on G3 calculations of stationary points on the C4H7 potential energy surface, were carried out to predict rate coefficients and product branching fractions. The predicted branching to 1-methylallyl product is relatively small under the conditions of the present experiments but increases as the pressure is lowered. Analysis of end products of 248 nm photolysis of vinyl iodide/ethylene mixtures at total pressures between 27 and 933 mbar provides no direct evidence for participation of 1-methylallyl.
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Affiliation(s)
- Huzeifa Ismail
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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88
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Bilera IV, Borisov YA, Buravtsev NN, Kolbanovskii YA. Renner-teller effect at the initial acetylene thermal transformation stages. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2007. [DOI: 10.1134/s1990793107020017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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89
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Grant DJ, Dixon DA. Sigma- and pi-bond strengths in main group 3-5 compounds. J Phys Chem A 2007; 110:12955-62. [PMID: 17125312 DOI: 10.1021/jp065085q] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The sigma- and pi-bond strengths for the molecules BH2NH2, BH2PH2, AlH2NH2, and AlH2PH2 have been calculated by using ab initio molecular electronic structure theory at the CCSD(T)/CBS level. The adiabatic pi-bond energy is defined as the rotation barrier between the equilibrium ground-state configuration and the C(s)symmetry transition state for torsion about the A-X bond. We also report intrinsic pi-bond energies corresponding to the adiabatic rotation barrier corrected for the inversion barrier at N or P. The adiabatic sigma-bond energy is defined as the dissociation energy of AH2XH2 to AH2 + XH2 in their ground states minus the adiabatic pi-bond energy. The adiabatic sigma-bond strengths for the molecules BH2NH2, BH2PH2, AlH2NH2, and AlH2PH2 are 109.8, 98.8, 77.6, and 68.3 kcal/mol, respectively, and the corresponding adiabatic pi-bond strengths are 29.9, 10.5, 9.2, and 2.7 kcal/mol, respectively.
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Affiliation(s)
- Daniel J Grant
- Department of Chemistry, Shelby Hall, The University of Alabama, P.O. Box 870336, Tuscaloosa, AL 35487-0336, USA
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90
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Abstract
The gas-phase acidities of the vinyl hydrogens of cis- and trans-2-butene were measured by the silane kinetic method in a Fourier-transform ion cyclotron resonance spectrometer. The acidities of ethene and the secondary vinyl hydrogen of propene were measured by the same method. The method was calibrated using the known acidities of methane and benzene. The vinyl hydrogens of trans-2-butene are more acidic than the vinyl hydrogens of cis-2-butene by 4.5 kcal/mol; the acidities of ethene and the secondary vinyl hydrogen of propene are between those of the two butenes. The acidity of cis-2-butene is 409 +/- 2 kcal/mol, and the acidity of trans-2-butene is 405 +/- 2 kcal/mol. Density functional theory calculations are in good agreement with the experiments. The results are discussed in terms of steric interactions, polarizabilities, dipole-dipole interactions, and charge-dipole interactions.
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Affiliation(s)
- David A Walthall
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
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91
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92
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Ghosh R, Zhang X, Achord P, Emge TJ, Krogh-Jespersen K, Goldman AS. Dimerization of Alkynes Promoted by a Pincer-Ligated Iridium Complex. C−C Reductive Elimination Inhibited by Steric Crowding. J Am Chem Soc 2007; 129:853-66. [PMID: 17243822 DOI: 10.1021/ja0647194] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The pincer-ligated species (PCP)Ir (PCP = kappa3-C6H3-2,6-(CH2PtBu2)2) is found to promote dimerization of phenylacetylene to give the enyne complex (PCP)Ir(trans-1,4-phenyl-but-3-ene-1-yne). The mechanism of this reaction is found to proceed through three steps: (i) addition of the alkynyl C-H bond to iridium, (ii) insertion of a second phenylacetylene molecule into the resulting Ir-H bond, and (iii) vinyl-acetylide reductive elimination. Each of these steps has been investigated, by both experimental and computational (DFT) methods, to yield unexpected conclusions of general interest. (i) The product of alkynyl C-H addition, (PCP)Ir(CCPh)(H) (3), has been isolated and, in accord with experimental observations, is calculated to be 29 kcal/mol more stable than the analogous product of benzene C-H addition. (ii) Insertion of a second PhCCH molecule into the Ir-H bond of 3 proceeds rapidly, but with a 1,2-orientation. This orientation gives (PCP)Ir(CCPh)(CPh=CH2) (4) which would yield the 1,3-diphenyl-enyne if it were to undergo C-C elimination; however, the insertion is reversible, which represents the first example, to our knowledge, of simple beta-H elimination from a vinyl group to give a terminal hydride. The 2,1-insertion product (PCP)Ir(CCPh)(CH=CHPh) (6) forms more slowly, but unlike the 1,2 insertion product it undergoes C-C elimination to give the observed enyne. (iii) The failure of 4 to undergo C-C elimination is found to be general for (PCP)Ir(CCPh)(vinyl) complexes in which the vinyl group has an alpha-substituent. Thus, although C-C elimination relieves crowding, the reaction is inhibited by increased crowding. Density-functional theory (DFT) calculations support this surprising conclusion and offer a clear explanation. Alkynyl-vinyl bond formation in the C-C elimination transition state involves the vinyl group pi-system; this requires that the vinyl group must rotate (around the Ir-C bond) by ca. 90 degrees to achieve an appropriate orientation. This rotation is severely inhibited by steric crowding, particularly when the vinyl group bears an alpha-substituent.
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Affiliation(s)
- Rajshekhar Ghosh
- Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA
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93
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Matus MH, Nguyen MT, Dixon DA. Theoretical Prediction of the Heats of Formation of C2H5O• Radicals Derived from Ethanol and of the Kinetics of β-C−C Scission in the Ethoxy Radical. J Phys Chem A 2006; 111:113-26. [PMID: 17201394 DOI: 10.1021/jp064086f] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Thermochemical parameters of three C(2)H(5)O* radicals derived from ethanol were reevaluated using coupled-cluster theory CCSD(T) calculations, with the aug-cc-pVnZ (n = D, T, Q) basis sets, that allow the CC energies to be extrapolated at the CBS limit. Theoretical results obtained for methanol and two CH(3)O* radicals were found to agree within +/-0.5 kcal/mol with the experiment values. A set of consistent values was determined for ethanol and its radicals: (a) heats of formation (298 K) DeltaHf(C(2)H(5)OH) = -56.4 +/- 0.8 kcal/mol (exptl: -56.21 +/- 0.12 kcal/mol), DeltaHf(CH(3)C*HOH) = -13.1 +/- 0.8 kcal/mol, DeltaHf(C*H(2)CH(2)OH) = -6.2 +/- 0.8 kcal/mol, and DeltaHf(CH(3)CH(2)O*) = -2.7 +/- 0.8 kcal/mol; (b) bond dissociation energies (BDEs) of ethanol (0 K) BDE(CH(3)CHOH-H) = 93.9 +/- 0.8 kcal/mol, BDE(CH(2)CH(2)OH-H) = 100.6 +/- 0.8 kcal/mol, and BDE(CH(3)CH(2)O-H) = 104.5 +/- 0.8 kcal/mol. The present results support the experimental ionization energies and electron affinities of the radicals, and appearance energy of (CH(3)CHOH+) cation. Beta-C-C bond scission in the ethoxy radical, CH(3)CH2O*, leading to the formation of C*H3 and CH(2)=O, is characterized by a C-C bond energy of 9.6 kcal/mol at 0 K, a zero-point-corrected energy barrier of E0++ = 17.2 kcal/mol, an activation energy of Ea = 18.0 kcal/mol and a high-pressure thermal rate coefficient of k(infinity)(298 K) = 3.9 s(-1), including a tunneling correction. The latter value is in excellent agreement with the value of 5.2 s(-1) from the most recent experimental kinetic data. Using RRKM theory, we obtain a general rate expression of k(T,p) = 1.26 x 10(9)p(0.793) exp(-15.5/RT) s(-1) in the temperature range (T) from 198 to 1998 K and pressure range (p) from 0.1 to 8360.1 Torr with N2 as the collision partners, where k(298 K, 760 Torr) = 2.7 s(-1), without tunneling and k = 3.2 s(-1) with the tunneling correction. Evidence is provided that heavy atom tunneling can play a role in the rate constant for beta-C-C bond scission in alkoxy radicals.
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Affiliation(s)
- Myrna H Matus
- Department of Chemistry, University of Alabama, Tuscaloosa, Alabama 35487-0336, USA
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94
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Affiliation(s)
- Paul G Wenthold
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.
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95
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Abstract
Experiments are reviewed in which key problems in chemical dynamics are probed by experiments based on photodetachment and/or photoexcitation of negative ions. Examples include transition state spectroscopy of biomolecular reactions, spectroscopy of open shell van der Waals complexes, photodissociation of free radicals, and time-resolved dynamics in clusters. The experimental methods used in these investigations are described along with representative systems that have been studied.
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Affiliation(s)
- Daniel M Neumark
- Department of Chemistry,University of California, Berkeley, California 94720, USA.
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96
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De Angelis F, Fantacci S, Sgamellotti A. Ab initio molecular dynamics simulations of organometallic reactivity. Coord Chem Rev 2006. [DOI: 10.1016/j.ccr.2006.02.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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97
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Lago AF, Baer T. A Photoelectron Photoion Coincidence Study of the Vinyl Bromide and Tribromoethane Ion Dissociation Dynamics: Heats of Formation of C2H3+, C2H3Br, C2H3Br+, C2H3Br2+, and C2H3Br3. J Phys Chem A 2005; 110:3036-41. [PMID: 16509625 DOI: 10.1021/jp053943x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The threshold photoelectron photoion coincidence (TPEPICO) technique has been used to measure accurate dissociative photoionization onsets of vinyl bromide and 1,1,2-tribromoethane. The reactions investigated and their 0 K onsets are C2H3Br + hnu --> C2H3+ + Br (11.902 +/- 0.008 eV); C2H3Br3 + hnu --> C2H3Br2+ + Br (10.608 +/- 0.008 eV); and (C2H3Br3 + hnu --> C2H3Br+ + 2Br (12.301 +/- 0.035 eV). The vinyl ion heat of formation (Delta(f)H degrees 298K = 1116.1 +/- 3.0 kJ/mol) has been calculated using W1 theory and used as an anchor along with the measured dissociation energies to determine the heats of formation, Delta(f)H degrees 298K, in kJ/mol, of the following bromine-containing species: C2H3Br (74.1 +/- 3.1), C2H3Br+ (1021.9 +/- 3.1), C2H3Br2+ (967.1 +/- 4.0), and C2H3Br3 (53.5 +/- 4.3). These results represent accurate and consistent experimental determinations of heats of formation for these bromine-containing species, which serve to correct the discrepancies in the literature for C2H3Br and C2H3Br+ and provide the first experimental determination for the enthalpies of formation of C2H3Br2+ and C2H3Br3.
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Affiliation(s)
- A F Lago
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
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Taatjes CA, Hansen N, Miller JA, Cool TA, Wang J, Westmoreland PR, Law ME, Kasper T, Kohse-Höinghaus K. Combustion Chemistry of Enols: Possible Ethenol Precursors in Flames. J Phys Chem A 2005; 110:3254-60. [PMID: 16509650 DOI: 10.1021/jp0547313] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Before the recent discovery that enols are intermediates in many flames, they appeared in no combustion models. Furthermore, little is known about enols' flame chemistry. Enol formation in low-pressure flames takes place in the preheat zone, and its precursors are most likely fuel species or the early products of fuel decomposition. The OH + ethene reaction has been shown to dominate ethenol production in ethene flames although this reaction has appeared insufficient to describe ethenol formation in all hydrocarbon oxidation systems. In this work, the mole fraction profiles of ethenol in several representative low-pressure flames are correlated with those of possible precursor species as a means for judging likely formation pathways in flames. These correlations and modeling suggest that the reaction of OH with ethene is in fact the dominant source of ethenol in many hydrocarbon flames, and that addition-elimination reactions of OH with other alkenes are also likely to be responsible for enol formation in flames. On this basis, enols are predicted to be minor intermediates in most flames and should be most prevalent in olefinic flames where reactions of the fuel with OH can produce enols directly.
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Affiliation(s)
- Craig A Taatjes
- Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, USA
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100
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Faulhaber AE, Szpunar DE, Kautzman KE, Neumark DM. Photodissociation Dynamics of the Ethoxy Radical Investigated by Photofragment Coincidence Imaging. J Phys Chem A 2005; 109:10239-48. [PMID: 16833317 DOI: 10.1021/jp053212x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The photodissociation dynamics of the ethoxy radical (CH3CH2O) have been studied at energies from 5.17 to 5.96 eV using photofragment coincidence imaging. The upper state of the electronic transition excited at these energies is assigned to the C2A''state on the basis of electronic structure calculations. Fragment mass distributions show two photodissociation channels, OH + C2H4 and CH3 + CH2O. The presence of an additional photodissociation channel, identified as D + C2D4O, is revealed in time-of-flight distributions from the photodissociation of CD3CD2O. The product branching ratios and fragment translational energy distributions for all of the observed mass channels are nonstatistical. Moreover, the significant yield of OH + C2H4 product suggests that the mechanism for this channel involves isomerization on the excited-state surface. Photodissociation at a much lower yield is seen following excitation at 3.91 eV, corresponding to a vibronic band of the B2A' <-- X2A'' transition.
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Affiliation(s)
- Ann Elise Faulhaber
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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