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Stamm J, Kwon S, Sandhu S, Shaik M, Das R, Sandhu J, Curenton B, Wicka C, Levine BG, Sun L, Dantus M. The Surprising Dynamics of the McLafferty Rearrangement. J Phys Chem Lett 2023; 14:10088-10093. [PMID: 37917859 DOI: 10.1021/acs.jpclett.3c02102] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
We report femtosecond time-resolved measurements of the McLafferty rearrangement following the strong-field tunnel ionization of 2-pentanone, 4-methyl-2-pentanone, and 4,4-dimethyl-2-pentanone. The pump-probe-dependent yields of the McLafferty product ion are fit to a biexponential function with fast (∼100 fs) and slow (∼10 ps) time constants, the latter of which is faster for the latter two compounds. Following nearly instantaneous ionization, the fast time scale is associated with rotation of the molecule to a six-membered cyclic intermediate that facilitates transfer of the γ-hydrogen, while the ∼50-100 times longer time scale is associated with a π-bond rearrangement and bond cleavage between the α- and β-carbons to produce the enol cation. These experimental measurements are supported by ab initio molecular dynamics trajectories, which further confirm the time scale of this important stepwise reaction in mass spectrometry.
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Affiliation(s)
- Jacob Stamm
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Sung Kwon
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Shawn Sandhu
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Moaid Shaik
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Rituparna Das
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jesse Sandhu
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Bradley Curenton
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Clayton Wicka
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Benjamin G Levine
- Department of Chemistry and Institute of Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, United States
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Marcos Dantus
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, United States
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2
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Jensen SC, Friend CM. The Dynamic Roles of Interstitial and Surface Defects on Oxidation and Reduction Reactions on Titania. Top Catal 2013. [DOI: 10.1007/s11244-013-0135-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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3
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Cui G, Lu Y, Thiel W. Electronic excitation energies, three-state intersections, and photodissociation mechanisms of benzaldehyde and acetophenone. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.04.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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4
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Tadić JM, Moortgat GK, Bera PP, Loewenstein M, Yates EL, Lee TJ. Photochemistry and Photophysics of n-Butanal, 3-Methylbutanal, and 3,3-Dimethylbutanal: Experimental and Theoretical Study. J Phys Chem A 2011; 116:5830-9. [DOI: 10.1021/jp208665v] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Jovan M. Tadić
- NASA Ames Research Center, Moffett Field, Mountain View, California 94035, United States
| | - Geert K. Moortgat
- Atmospheric Chemistry Department, Max-Planck-Institut für Chemie, P.O. Box 3060, 55020 Mainz, Germany
| | - Partha P. Bera
- NASA Ames Research Center, Moffett Field, Mountain View, California 94035, United States
| | - Max Loewenstein
- NASA Ames Research Center, Moffett Field, Mountain View, California 94035, United States
| | - Emma L. Yates
- NASA Ames Research Center, Moffett Field, Mountain View, California 94035, United States
| | - Timothy J. Lee
- NASA Ames Research Center, Moffett Field, Mountain View, California 94035, United States
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Cui G, Sun Z, Fang W. Adiabatic and Nonadiabatic Bond Cleavages in Norrish Type I Reaction. J Phys Chem A 2011; 115:10146-53. [DOI: 10.1021/jp2053025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ganglong Cui
- Chemistry College, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Zhigang Sun
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China
| | - Weihai Fang
- Chemistry College, Beijing Normal University, Beijing 100875, People's Republic of China
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Abe M, Kubo E, Nozaki K, Matsuo T, Hayashi T. An Extremely Long-Lived Singlet 4,4-Dimethoxy-3,5-diphenylpyrazolidine-3,5-diyl Derivative: A Notable Nitrogen-Atom Effect on Intra- and Intermolecular Reactivity. Angew Chem Int Ed Engl 2006; 45:7828-31. [PMID: 17061308 DOI: 10.1002/anie.200603287] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Manabu Abe
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University (HANDAI), 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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An Extremely Long-Lived Singlet 4,4-Dimethoxy-3,5-diphenylpyrazolidine-3,5-diyl Derivative: A Notable Nitrogen-Atom Effect on Intra- and Intermolecular Reactivity. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200603287] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Griesbeck AG, Heckroth H. Stereoselective synthesis of 2-aminocyclobutanols via photocyclization of alpha-amido alkylaryl ketones: mechanistic implications for the Norrish/Yang reaction. J Am Chem Soc 2002; 124:396-403. [PMID: 11792208 DOI: 10.1021/ja0111941] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of chiral N-acylated alpha-amino p-methylbutyrophenone derivatives 1a-1h was synthesized from alpha-amino acids via a three-step procedure. These substrates were photolyzed in benzene and gave Norrish II and Norrish I cleavage products as well as the N-acylated 2-aminocyclobutanols that derive from gamma-hydrogen abstraction and 1,4-triplet biradical combination (Yang cyclization). The products were formed with characteristic Yang/cleavage ratios. The quantum yields for the photodecomposition of the N-acetyl-protected substrates 1b,e,f were moderate (12-26%); the diastereoselectivities of the cyclobutanol formation were remarkably high for all substrates. High diastereospecificity was observed for the isoleucine derivatives (2S,3S)-1g and allo-(2S,3R)-1g; the Yang reaction dominated the photochemistry of allo-1g, whereas 1ggave preferentially Norrish II cleavage. The role of hydrogen bonding as one of the stereodirecting effects was demonstrated by comparison of the cyclization efficiency of the valine derivative 1e with 1h,i,j. Also, aromatic beta-keto esters gave the Yang cyclization products in low yields. The diastereoselectivity of the cyclobutanol formation was rationalized by a three-step mechanism where every step is connected with one distinct stereochemical induction mechanism: (a) diastereoselective hydrogen abstraction, (b) conformational equilibration of the 1,4-tetramethylene biradicals (as calculated by semiempiric methods) controlled by hydrogen bonding, and (c) diastereoselective biradical combination (versus cleavage) influenced by spin-orbit coupling controlled intersystem crossing geometries.
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Affiliation(s)
- Axel G Griesbeck
- Institute of Organic Chemistry, Greinstrasse 4, D-50939 Köln, Germany.
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Sølling TI, Diau EWG, Kötting C, De Feyter S, Zewail AH. Femtochemistry of Norrish type-I reactions: IV. Highly excited ketones--experimental. Chemphyschem 2002; 3:79-97. [PMID: 12465478 DOI: 10.1002/1439-7641(20020118)3:1<79::aid-cphc79>3.0.co;2-#] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Femtosecond dynamics of Norrish type-I reactions of cyclic and acyclic ketones have been investigated in real time for a series of 13 compounds using femtosecond-resolved time-of-flight mass spectrometry. A general physical description of the ultrafast processes of ketones excited into a high-lying Rydberg state is presented. It accounts not only for the results that are presented herein but also for the results of previously reported studies. For highly excited ketones, we show that the Norrish type-I reaction is nonconcerted, and that the first bond breakage occurs along the effectively repulsive S2 surface involving the C-C bond in a manner which is similar to that of ketones in the S1 state (E. W.-G. Diau et al. ChemPhysChem 2001, 2, 273-293). The experimental results show that the wave packet motion out of the initial Franck-Condon region and down to the S2 state can be resolved. This femtosecond (fs) internal conversion from the highly excited Rydberg state to the S2 state proceeds through conical intersections (Rydberg-valence) that are accessed through the C=O stretching motion. In one of these conical intersections, the internal energy is guided into an asymmetric stretching mode. This explains the previously reported pronounced nonstatistical nature of the reaction. The second bond breakage involves an excited-state acyl radical and occurs on a time scale that is up to one order of magnitude longer than the first. We discuss the details regarding the ion chemistry, which determines the appearance of the mass spectra that arise from ionization on the fs time scale. The experimental results presented here, aided by the theoretical work reported in paper III, provide a unified picture of Norrish reactions on excited states and on the ground-state potential energy surfaces.
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Affiliation(s)
- Theis I Sølling
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA.
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Sølling TI, Diau EWG, Kötting C, De Feyter S, Zewail AH. Femtochemistry of Norrish Type-I Reactions: IV. Highly Excited Ketones—Experimental. Chemphyschem 2002. [DOI: 10.1002/1439-7641(20020118)3:1<79::aid-cphc79>3.0.co;2-%23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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11
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Sølling TI, Diau EW, Kötting C, De Feyter S, Zewail AH. Femtochemistry of Norrish Type‐I Reactions: IV. Highly Excited Ketones—Experimental. Chemphyschem 2002. [DOI: 10.1002/1439-7641(20020118)3:1%3c79::aid-cphc79%3e3.0.co;2-%23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Theis I. Sølling
- Arthur Amos Noyes Laboratory of Chemical Physics California Institute of Technology Pasadena, CA 91125, (USA) Fax: (+1) 626‐792‐8456 http://www.its.caltech.edu/∼femto/
| | - Eric W.‐G. Diau
- Arthur Amos Noyes Laboratory of Chemical Physics California Institute of Technology Pasadena, CA 91125, (USA) Fax: (+1) 626‐792‐8456 http://www.its.caltech.edu/∼femto/
| | - Carsten Kötting
- Arthur Amos Noyes Laboratory of Chemical Physics California Institute of Technology Pasadena, CA 91125, (USA) Fax: (+1) 626‐792‐8456 http://www.its.caltech.edu/∼femto/
| | - Steven De Feyter
- Arthur Amos Noyes Laboratory of Chemical Physics California Institute of Technology Pasadena, CA 91125, (USA) Fax: (+1) 626‐792‐8456 http://www.its.caltech.edu/∼femto/
| | - Ahmed H. Zewail
- Arthur Amos Noyes Laboratory of Chemical Physics California Institute of Technology Pasadena, CA 91125, (USA) Fax: (+1) 626‐792‐8456 http://www.its.caltech.edu/∼femto/
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Sinicropi A, Pogni R, Basosi R, Robb MA, Gramlich G, Nau WM, Olivucci M. Fluoreszenzlöschung über stufenweisen Wasserstoff-, Elektronen- und Protonentransfer in der Nähe einer konischen Durchdringung. Angew Chem Int Ed Engl 2001. [DOI: 10.1002/1521-3757(20011119)113:22<4313::aid-ange4313>3.0.co;2-l] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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13
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Sinicropi A, Pogni R, Basosi R, Robb MA, Gramlich G, Nau WM, Olivucci M. Fluorescence Quenching by Sequential Hydrogen, Electron, and Proton Transfer in the Proximity of a Conical Intersection. Angew Chem Int Ed Engl 2001; 40:4185-4189. [DOI: 10.1002/1521-3773(20011119)40:22<4185::aid-anie4185>3.0.co;2-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2001] [Indexed: 11/12/2022]
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Sinicropi A, Pischel U, Basosi R, Nau WM, Olivucci M. Conical Intersections in Charge-Transfer Induced Quenching This work was supported by the Swiss National Science Foundation (Projects 52489.98, 54108.98, and 58000.99), the Fonds der Chemischen Industrie, the Università di Siena (Progetto di Ateneo A.A. 99/00), and NATO (CRG 950748). Angew Chem Int Ed Engl 2000; 39:4582-4586. [PMID: 11169677 DOI: 10.1002/1521-3773(20001215)39:24<4582::aid-anie4582>3.0.co;2-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Adalgisa Sinicropi
- Dipartimento di Chimica, Università degli Studi di Siena via Aldo Moro, 53100 Siena (Italy)
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Sinicropi A, Pischel U, Basosi R, Nau WM, Olivucci M. Konische Durchdringungen in Charge-Transfer-induzierten Photoreaktionen. Angew Chem Int Ed Engl 2000. [DOI: 10.1002/1521-3757(20001215)112:24<4776::aid-ange4776>3.0.co;2-h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Zewail A. Femtochemie: Studium der Dynamik der chemischen Bindung auf atomarer Skala mit Hilfe ultrakurzer Laserpulse (Nobel-Aufsatz). Angew Chem Int Ed Engl 2000. [DOI: 10.1002/1521-3757(20000804)112:15<2688::aid-ange2688>3.0.co;2-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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