1
|
Li S, Jochim B, Jackson JE, Dantus M. Femtosecond dynamics and coherence of ionic retro-Diels-Alder reactions. J Chem Phys 2021; 155:044303. [PMID: 34340396 DOI: 10.1063/5.0048380] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ultrafast tunnel ionization enables femtosecond time-resolved dynamic measurements of the retro-Diels-Alder reactions of positively charged cyclohexene, norbornene, and dicyclopentadiene. Unlike the reaction times of 500-600 ps that are observed following UV excitation of neutral species, on the ionic potential energy surfaces, these reactions occur on a single picosecond timescale and, in some cases, exhibit vibrational coherence. In the case of norbornene, a 270 cm-1 vibrational mode is found to modulate the retro-Diels-Alder reaction.
Collapse
Affiliation(s)
- Shuai Li
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Bethany Jochim
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - James E Jackson
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Marcos Dantus
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| |
Collapse
|
2
|
Hammer N, Christensen ML, Chen Y, Naharro D, Liu F, Jørgensen KA, Houk KN. An Experimental Stereoselective Photochemical [1s,3s]-Sigmatropic Silyl Shift and the Existence of Silyl/Allyl Conical Intersections. J Am Chem Soc 2020; 142:6030-6035. [PMID: 32191462 DOI: 10.1021/jacs.9b11579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report an experimental discovery and computational investigation of the first photochemical stereoselective [1,3]-sigmatropic silyl shift of an allylsilane. An organocatalytic enantioselective cascade annulation generates a trimethylsilyl-o-isotoluene reactant in >99:1 e.r., and this trimethylsilyl-o-isotoluene contains an allylic silane moiety that undergoes a stereoselective photochemical [1,3]-silyl shift to form a benzylsilane with 96:4 e.r. The mechanism of this unprecedented [1,3]-silyl shift has been elucidated by a series of experimental studies and CASSCF, DFT, and TD-DFT calculations on model systems and the experimental system. The highly stereoselective photoreaction is proposed to occur via a singlet silyl/allyl conical intersection. This is a new demonstration of the role of conical intersections in selective photochemistry.
Collapse
Affiliation(s)
- Niels Hammer
- Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark
| | | | - Yu Chen
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Daniel Naharro
- Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Fang Liu
- College of Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | | | - K N Houk
- Department of Chemistry and Biochemistry, and Department of Biochemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, United States
| |
Collapse
|
3
|
Blancafort L. Photochemistry and photophysics at extended seams of conical intersection. Chemphyschem 2014; 15:3166-81. [PMID: 25157686 DOI: 10.1002/cphc.201402359] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Indexed: 11/07/2022]
Abstract
The role of extended seams of conical intersection in excited-state mechanisms is reviewed. Seams are crossings of the potential energy surface in many dimensions where the decay from the excited to the ground state can occur, and the extended seam is composed of different segments lying along a reaction coordinate. Every segment is associated with a different primary photoproduct, which gives rise to competing pathways. This idea is first illustrated for fulvene and ethylene, and then it is used to explain more complex cases such as the dependence of the isomerisation of retinal chromophore isomers on the protein environment, the dependence of the efficiency of the azobenzene photochemical switch on the wavelength of irradiation and the direction of the isomerisation, and the coexistence of different mechanisms in the photo-induced Wolff rearrangement of diazonaphthoquinone. The role of extended seams in the photophysics of the DNA nucleobases and the relationship between two-state seams and three-state crossings is also discussed. As an outlook, the design of optical control strategies based on the passage of the excited molecule through the seam is considered, and it is shown how the excited-state lifetime of fulvene can be modulated by shaping the energy of the seam.
Collapse
Affiliation(s)
- Lluís Blancafort
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071 Girona (Spain).
| |
Collapse
|
4
|
Rodríguez-Hernández F, Martínez-Mesa A, Uranga-Piña L. Hybrid quantum–classical study of the non-adiabatic cis–trans photoisomerization in a model polyatomic molecule. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2013.11.062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
5
|
Schalk O, Boguslavskiy AE, Schuurman MS, Brogaard RY, Unterreiner AN, Wrona-Piotrowicz A, Werstiuk NH, Stolow A. Substituent Effects on Dynamics at Conical Intersections: Cycloheptatrienes. J Phys Chem A 2013; 117:10239-47. [DOI: 10.1021/jp309875m] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Oliver Schalk
- AlbaNova
University Centre, Stockholm University, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
- National Research
Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
- Institut
für BioMolekulare Optik, Ludwig-Maximilians-Universität, Oettingen Str. 67, 80538 München, Germany
| | | | - Michael S. Schuurman
- National Research
Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Rasmus Y. Brogaard
- Department
of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 København, Denmark
| | - Andreas N. Unterreiner
- Institute
of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 2, 76131 Karlsruhe, Germany
| | - Anna Wrona-Piotrowicz
- Department
of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - Nick H. Werstiuk
- Department
of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - Albert Stolow
- National Research
Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| |
Collapse
|
6
|
Sellner B, Barbatti M, Müller T, Domcke W, Lischka H. Ultrafast non-adiabatic dynamics of ethylene including Rydberg states. Mol Phys 2013. [DOI: 10.1080/00268976.2013.813590] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
7
|
Mori T, Martínez TJ. Exploring the Conical Intersection Seam: The Seam Space Nudged Elastic Band Method. J Chem Theory Comput 2013; 9:1155-63. [DOI: 10.1021/ct300892t] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Toshifumi Mori
- PULSE Institute and
Department
of Chemistry, Stanford University, Stanford, California 94305, United
States
- SLAC National Accelerator
Laboratory,
2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Todd. J. Martínez
- PULSE Institute and
Department
of Chemistry, Stanford University, Stanford, California 94305, United
States
- SLAC National Accelerator
Laboratory,
2575 Sand Hill Road, Menlo Park, California 94025, United States
| |
Collapse
|
8
|
Gerbig D, Ley D. Computational methods for contemporary carbene chemistry. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2012. [DOI: 10.1002/wcms.1124] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
|
9
|
Plasser F, Barbatti M, Aquino AJA, Lischka H. Electronically excited states and photodynamics: a continuing challenge. Theor Chem Acc 2012. [DOI: 10.1007/s00214-011-1073-y] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
10
|
Schalk O, Boguslavskiy AE, Stolow A, Schuurman MS. Through-Bond Interactions and the Localization of Excited-State Dynamics. J Am Chem Soc 2011; 133:16451-8. [DOI: 10.1021/ja1114002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Oliver Schalk
- Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Dr., Ottawa, Ontario K1A 0R6, Canada
| | - Andrey E. Boguslavskiy
- Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Dr., Ottawa, Ontario K1A 0R6, Canada
| | - Albert Stolow
- Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Dr., Ottawa, Ontario K1A 0R6, Canada
| | - Michael S. Schuurman
- Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Dr., Ottawa, Ontario K1A 0R6, Canada
| |
Collapse
|
11
|
Su MD. A computational study of the mechanisms of the photoisomerization reactions of monocyclic and bicyclic olefins. J Phys Chem A 2011; 115:5157-65. [PMID: 21539344 DOI: 10.1021/jp109543q] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mechanisms of the photochemical isomerization reactions were investigated theoretically using a model system of cyclohexene (1), cycloheptene (2), norbornene (3), and two bicyclic olefins (4 and 5) using the CASSCF (six-electron/six-orbital active space) and MP2-CAS methods with the 6-311(d,p) basis set. The structures of the conical intersections, which play a decisive role in such photoisomerizations, were obtained. The intermediates and transition structures of the ground state were also calculated to assist in providing a qualitative explanation of the reaction pathways. Two photoreaction pathways were examined in the present work. The first can produce a photoproduct with an extra ring. The other can yield a photoproduct with a smaller ring with an external double bond. Both pathways involve cyclic carbene intermediates. Also, our model investigations suggest that both reaction pathways follow a similar photochemical pattern as follows: reactant → Franck-Condon region → conical intersection → cyclic carbene intermediate → transition state → photoproduct. Moreover, these two reaction pathways can compete with each other since the energetics of their conical intersection points are quite similar. Our present theoretical results agree with the available experimental observations.
Collapse
Affiliation(s)
- Ming-Der Su
- Department of Applied Chemistry, National Chiayi University, Chiayi, Taiwan.
| |
Collapse
|
12
|
Blancafort L, Lasorne B, Bearpark MJ, Worth GA, Robb MA. Second-Order Analysis of Conical Intersections: Applications to Photochemistry and Photophysics of Organic Molecules. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/978-3-642-03432-9_7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
|
13
|
Rossi AR, Wang Y, Wiberg KB. Excited States and Photochemistry of Bicyclo[1.1.0]butane. J Phys Chem A 2009; 113:1686-95. [DOI: 10.1021/jp807407c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Angelo R. Rossi
- Department of Chemistry The City University of New York - York College Jamaica, New York 11451
| | - Yigui Wang
- Department of Chemistry Yale University New Haven, Connecticut 06520-8197
| | - Kenneth B. Wiberg
- Department of Chemistry Yale University New Haven, Connecticut 06520-8197
| |
Collapse
|
14
|
Kosma K, Trushin SA, Fuss W, Schmid WE. Ultrafast Dynamics and Coherent Oscillations in Ethylene and Ethylene-d4 Excited at 162 nm. J Phys Chem A 2008; 112:7514-29. [DOI: 10.1021/jp803548c] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- K. Kosma
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
| | - S. A. Trushin
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
| | - W. Fuss
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
| | - W. E. Schmid
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
| |
Collapse
|
15
|
|
16
|
Su MD. A theoretical characterization of the photoisomerization channels of 1,2-cyclononadienes on both singlet and triplet potential-energy surfaces. Chemistry 2008; 13:9957-72. [PMID: 17879244 DOI: 10.1002/chem.200700646] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ground-, (1)(pipi*)-, and (3)(pipi*)-state potential-energy surfaces of 1,2-cyclononadiene and isomeric C(9)H(14) species, as well as 1-methyl-1,2-cyclononadiene and isomeric C(10)H(16) species were all mapped using CASSCF and the 6-31G(d) basis set. Theoretical results were found to be in good agreement with the available experimental observations for both 1,2-cyclononadiene and 1-methyl-1,2-cyclononadiene isomerization reactions under singlet and triplet direct or sensitized irradiation. Extremely efficient decay occurs from the first singlet excited state to the ground state through at least three different conical intersections (surface crossings). The first of these crossing points is accessed by a one-bond ring closure. From this conical intersection point (CI-A or CI-C), some possible subsequent ground-state reaction paths have been identified: 1) intramolecular C--H bond insertion to form the bicyclic photoproduct and 2) intramolecular C--H bond insertion to form tricyclic photoproducts. An excited state [1,3]-sigmatropic shift leads to the second conical intersection (CI-B or CI-E), which can give a three-bond cyclononyne species. Besides these, in the singlet photochemical reactions of 1-methyl-1,2-cyclononadiene, excited-state, one allenic C--H bond insertion leads to a third conical intersection (CI-D). Possible ground-state reaction pathways from this structure lead to the formation of a diene photoproduct or to transannular insertion photoproducts. Moreover, in the case of triplet 1,2-cyclononadiene and 1-methyl-1,2-cyclononadiene photoisomerization reactions, both chemical reactions will adopt a 1,3-biradical (T(1)/S(0)-1, T(1)/S(0)-2, and T(1)/S(0)-3), which may undergo intersystem crossings leading to the formation of tricyclic or bicyclic photoproducts. The results obtained allow a number of predictions to be made.
Collapse
Affiliation(s)
- Ming-Der Su
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan.
| |
Collapse
|
17
|
Nonadiabatic Excited-State Dynamics of Aromatic Heterocycles: Toward the Time-Resolved Simulation of Nucleobases. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/978-1-4020-8184-2_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
18
|
Barbatti M, Ruckenbauer M, Szymczak JJ, Aquino AJA, Lischka H. Nonadiabatic excited-state dynamics of polar π-systems and related model compounds of biological relevance. Phys Chem Chem Phys 2008; 10:482-94. [DOI: 10.1039/b709315m] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
19
|
Abstract
The standard model for photoinduced cis-trans isomerization about carbon double bonds is framed in terms of two electronic states and a one-dimensional reaction coordinate. We review recent work that suggests that a minimal picture of the reaction mechanism requires the consideration of at least two molecular coordinates and three electronic states. In this chapter, we emphasize the role of conical intersections and charge transfer in the photoisomerization mechanism.
Collapse
Affiliation(s)
- Benjamin G Levine
- Department of Chemistry, Beckman Institute, Center for Biophysics and Computational Biology, and Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA.
| | | |
Collapse
|
20
|
Wilsey S, Houk KN. H-Vinyl Conical Intersections for Dienes: A Mechanism for the Photochemical Hula Twist¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0760616hvcifd2.0.co2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
21
|
Norton JE, Houk KN. H/vinyl conical intersections of hexatrienes related to the hula-twist photoisomerization. Mol Phys 2007. [DOI: 10.1080/00268970500417606] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Joseph E. Norton
- a Department of Chemistry and Biochemistry , University of California , Los Angeles, CA 90095-1569, USA
| | - K. N. Houk
- a Department of Chemistry and Biochemistry , University of California , Los Angeles, CA 90095-1569, USA
| |
Collapse
|
22
|
White RC, Arney BE, White KM. Photochemistry of 1,2-Dihydronaphthalene Oxide: Concurrent Triplet and Singlet Processes via Singlet Excitation. J Org Chem 2006; 71:8173-7. [PMID: 17025308 DOI: 10.1021/jo0614184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photochemistry of 1,2-dihydronaphthalene oxide (254 nm) was reexamined and indan was found to be a primary photoproduct, as well as the traditionally assumed secondary photoproduct. Quenching studies demonstrated that indan, as a primary photoproduct, is derived from a triplet pathway, competing with a singlet route, back to the ground state surface. CASSCF calculations strongly suggest that the triplet pathway consists of a dissociation of the oxirane moiety to give a triplet carbene and aldehyde, which via hydrogen abstraction-decarbonylation-ISC recloses to give indan. Conical intersections corresponding to the presumed 1,2-hydrogen shift and 1,2-alkyl shift to give 2-tetralone and 1-indancarbaldehyde, respectively, were located computationally.
Collapse
Affiliation(s)
- Rick C White
- Department of Chemistry, Sam Houston State University, Huntsville, Texas 77341, USA.
| | | | | |
Collapse
|
23
|
Takahashi M. The mechanism of photochemical 1,3-silyl migration of allylsilane. J Phys Chem A 2005; 109:11902-6. [PMID: 16366641 DOI: 10.1021/jp053999r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photochemical reaction mechanisms of model compounds for 4-tert-butyl-1-(4-phenylphenyl)-1-(1,1-dimethylallyl)silacyclohexane are investigated using a complete active space comprised of six electrons in six orbitals with the standard 6-31G(d) basis set. It is concluded that the stereochemistry in the photochemical 1,3-silyl migrations of allylsilanes has a retention preference, in accord with the Woodward-Hoffmann rules. The calculated conical intersection (CI) structure suggests a dissociation path to radicals in addition to a 1,3-shift path. The bulkiness and rigidness of a silacyclohexane moiety does not affect the stereochemistry, but a slightly elongated Si-C bond length in the CI structure would promote the dissociation path.
Collapse
Affiliation(s)
- Masae Takahashi
- Photodynamics Research Center, The Institute of Physical and Chemical Research (RIKEN), 519-1399, Aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan.
| |
Collapse
|
24
|
Fuß W, Schmid W, Trushin S. Ultrafast photochemistry of cyclopentadiene: Competing hydrogen migration and electrocyclic ring closure. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2005.05.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
25
|
Barbatti M, Ruckenbauer M, Lischka H. The photodynamics of ethylene: A surface-hopping study on structural aspects. J Chem Phys 2005; 122:174307. [PMID: 15910032 DOI: 10.1063/1.1888573] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Simulations of the photodynamics of ethylene were carried out by employing the semiempirical direct trajectory with surface hopping method in order to assess quantitatively the importance of different regions of the S(2)S(1) and S(1)S(0) crossing seams. The results show that during the first 50 fs after a vertical photoexcitation to the pipi(*) state, the nonadiabatic coupling between the S(1) and the S(2) states produces a recurrence pattern of oscillation of the populations in these states. Within the first 100 fs, the S(1) state population spans a limited region of the configuration space between the initial geometries and the twisted-pyramidalized minimum on the crossing seam (MXS). Depending on the way of counting, about 50% of the S(1)-->S(0) transitions occur in the pyramidalized region of the crossing seam, but not necessarily close to the MXS. The remaining 50% occurs in the H-migration and ethylidene regions. Our analysis shows that the ethylidene region becomes more important in later stages of the dynamics when the flux of trajectories that was not effectively converted to the ground state in the pyramidalized region starts to reach this part of the configuration space. The excited-state nonadiabatic dynamics could be employed to generate suitable initial phase space distributions for the hot-ethylene ground-state kinetic studies.
Collapse
Affiliation(s)
- M Barbatti
- Institute for Theoretical Chemistry, University of Vienna, Austria.
| | | | | |
Collapse
|
26
|
Migani A, Sinicropi A, Ferré N, Cembran A, Garavelli M, Olivucci M. Structure of the intersection space associated with Z/E photoisomerization of retinal in rhodopsin proteins. Faraday Discuss 2004; 127:179-91. [PMID: 15471346 DOI: 10.1039/b315217k] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In this paper we employ a CASSCF/AMBER quantum-mechanics/molecular-mechanics tool to map the intersection space (IS) of a protein. In particular, we provide evidence that the S1 excited-state potential-energy surface of the visual photoreceptor rhodopsin is spanned by an IS segment located right at the bottom of the surface. Analysis of the molecular structures of the protein chromophore (a protonated Schiff base of retinal) along IS reveals a type of geometrical deformation not observed in vacuo. Such a structure suggests that conical intersections mediating different photochemical reactions reside along the same intersection space. This conjecture is investigated by mapping the intersection space of the rhodopsin chromophore model 2-Z-hepta-2,4,6-trieniminium cation and of the conjugated hydrocarbon 3-Z-deca-1,3,5,6,7-pentaene.
Collapse
Affiliation(s)
- Annapaola Migani
- Dipartimento di Chimica, Università di Siena, Via Aldo Moro, I-53100 Siena, Italy
| | | | | | | | | | | |
Collapse
|
27
|
Cook BH, Leigh WJ. The effect of central bond torsional mobility on the Rydberg state ring opening of alkylcyclobutenes. CAN J CHEM 2003. [DOI: 10.1139/v03-058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The stereochemistry of the π,R(3s) excited state ring opening of a series of bicyclic alkylcyclobutenes has been studied in hydrocarbon solution with 228 nm excitation. In these compounds, the C=C bond is shared between the cyclobutene ring and a five-, six-, or seven-membered ancillary ring, which has the effect of restricting the torsional mobility about the central CC bond in the isomeric diene products. It has previously been shown that monocyclic alkylcyclobutenes undergo stereospecific conrotatory ring opening upon excitation at the long wavelength edge of the π,R(3s) absorption band (228 nm), and nonstereospecific ring opening upon irradiation at shorter wavelengths (within the π,π* absorption band). Different behaviour is observed for the bicyclic systems studied in the present work. The bicyclo[3.2.0]hept-1-ene, bicyclo[4.2.0]oct-1-ene, and one of the bicyclo[5.2.0]non-1-ene derivatives yield nearly the same mixtures of E,E- and E,Z-diene isomers upon irradiation at 214 and 228 nm, with the product mixtures being heavily weighted in favor of the isomer(s) corresponding to disrotatory ring opening. The results may indicate that the stereochemical characteristics of the Rydberg-derived ring opening of alkylcyclobutenes depends on the ability of the molecule to twist about the "central" bond (i.e., the C=C bond in the cyclobutene) as ring opening proceeds. It is proposed that restricting the torsional mobility about the central bond activates internal conversion from the π,R(3s) to the π,π* potential energy surface, from which predominant disrotatory ring opening ensues.Key words: cyclobutene, Rydberg, ring opening, photopericyclic, electrocyclic.
Collapse
|
28
|
Quenneville J, Martínez TJ. Ab Initio Study of Cis−Trans Photoisomerization in Stilbene and Ethylene. J Phys Chem A 2003. [DOI: 10.1021/jp021210w] [Citation(s) in RCA: 228] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jason Quenneville
- Department of Chemistry and The Beckman Institute, University of Illinois, Urbana, Illinois 61801
| | - Todd J. Martínez
- Department of Chemistry and The Beckman Institute, University of Illinois, Urbana, Illinois 61801
| |
Collapse
|