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Neisser RW, Davis JP, Alfieri ME, Harkins H, Petit AS, Tabor DP, Kidwell NM. Photophysical Outcomes of Water-Solvated Heterocycles: Single-Conformation Ultraviolet and Infrared Spectroscopy of Microsolvated 2-Phenylpyrrole. J Phys Chem A 2023; 127:10540-10554. [PMID: 38085923 DOI: 10.1021/acs.jpca.3c04472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
The molecular chromophores within brown carbon (BrC) aerosols absorb solar radiation at visible and near-ultraviolet wavelengths. This contributes to the overall warming of the troposphere and the photochemical aging of aerosols. In this investigation, we combine a suite of experimental and theoretical methods to reveal the conformation-specific ultraviolet and infrared spectroscopy of 2-phenylpyrrole (2PhPy)─an extended π-conjugated pyrrole derivative and a model BrC chromophore─along with its water microsolvated molecular complexes (2PhPy:nH2O, n = 1-3). Using resonant two-photon ionization and double-resonance holeburning techniques alongside MP3 (ground state) and ADC(3) (excited state) torsional potential energy surfaces and discrete variable representation simulations, we characterized the ultraviolet spectra of 2PhPy and 2PhPy:1H2O. This analysis revealed evidence for Herzberg-Teller vibronic coupling along the CH wagging and NH stretching coordinates of the aromatic rings. Conformation-specific infrared spectroscopy revealed extended hydrogen-bonding networks of the 2PhPy:nH2O complexes. Upon stepwise addition of H2O solvation, the nearest H2O acceptor forms a strong, noncovalent interaction with the pyrrole NH donor, while the second and third H2O partners interface with the phenyl and pyrrole aromatic rings through growing van der Waals π/H atom stabilization. A local-mode Hamiltonian approach was employed for comparison with the experimental spectra, thus identifying the vibrational spectral signatures to specific 2PhPy:nH2O oscillators.
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Affiliation(s)
- Ruby W Neisser
- Department of Chemistry, The College of William & Mary, Williamsburg, Virginia 23187-8795, United States
| | - John P Davis
- Department of Chemistry, The College of William & Mary, Williamsburg, Virginia 23187-8795, United States
| | - Megan E Alfieri
- Department of Chemistry, The College of William & Mary, Williamsburg, Virginia 23187-8795, United States
| | - Hayden Harkins
- Department of Chemistry and Biochemistry, California State University─Fullerton, Fullerton, California 92834-6866, United States
| | - Andrew S Petit
- Department of Chemistry and Biochemistry, California State University─Fullerton, Fullerton, California 92834-6866, United States
| | - Daniel P Tabor
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Nathanael M Kidwell
- Department of Chemistry, The College of William & Mary, Williamsburg, Virginia 23187-8795, United States
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2
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León I, Montero R, Longarte A, Fernández JA. Revisiting the Spectroscopy of Water Dimer in Jets. J Phys Chem Lett 2021; 12:1316-1320. [PMID: 33535759 PMCID: PMC9157493 DOI: 10.1021/acs.jpclett.0c03001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 01/15/2021] [Indexed: 06/12/2023]
Abstract
Laser spectroscopy in jets is one of the main sources of structural data from molecular aggregates. Consequently, numerous and sophisticated experimental systems have been developed to extract precise information, which is usually interpreted in the light of quantum mechanical calculations. However, even with the most sophisticated experiments, it is sometimes difficult to interpret the experimental results. We present here the example of water dimer and how after almost 70 years, the assignment of its mass-resolved IR spectrum still generates controversy that extends toward the mechanism of ionization of water aggregates.
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Affiliation(s)
- Iker León
- Grupo
de Espectroscopía Molecular (GEM), Edificio Quifima, Unidad Asociada CSIC, Universidad de Valladolid, 47005 Valladolid, Spain
| | - Raúl Montero
- SGIKER
Laser Facility, University of the Basque
Country (UPV/EHU), Barrio Sarriena s/n, Leioa 48940, Spain
| | - Asier Longarte
- Department
of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa 48940, Spain
| | - José A. Fernández
- Department
of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa 48940, Spain
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3
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Geng T, Ehrmaier J, Schalk O, Richings GW, Hansson T, Worth G, Thomas RD. Time-Resolved Photoelectron Spectroscopy Studies of Isoxazole and Oxazole. J Phys Chem A 2020; 124:3984-3992. [PMID: 32242664 PMCID: PMC7304896 DOI: 10.1021/acs.jpca.9b11788] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The
excited state relaxation pathways of isoxazole and oxazole
upon excitation with UV-light were investigated by nonadiabatic ab
initio dynamics simulations and time-resolved photoelectron spectroscopy.
Excitation of the bright ππ*-state of isoxazole predominantly
leads to ring-opening dynamics. Both the initially excited ππ*-state
and the dissociative πσ*-state offer a combined barrier-free
reaction pathway, such that ring-opening, defined as a distance of
more than 2 Å between two neighboring atoms, occurs within 45
fs. For oxazole, in contrast, the excited state dynamics is about
twice as slow (85 fs) and the quantum yield for ring-opening is lower.
This is caused by a small barrier between the ππ*-state
and the πσ*-state along the reaction path, which suppresses
direct ring-opening. Theoretical findings are consistent with the
measured time-resolved photoelectron spectra, confirming the timescales
and the quantum yields for the ring-opening channel. The results indicate
that a combination of time-resolved photoelectron spectroscopy and
excited state dynamics simulations can explain the dominant reaction
pathways for this class of molecules. As a general rule, we suggest
that the antibonding σ*-orbital located between the oxygen atom
and a neighboring atom of a five-membered heterocyclic system provides
a driving force for ring-opening reactions, which is modified by the
presence and position of additional nitrogen atoms.
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Affiliation(s)
- Ting Geng
- Department of Physics, AlbaNova University Centre, Stockholm University, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| | - Johannes Ehrmaier
- Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Oliver Schalk
- Department of Physics, AlbaNova University Centre, Stockholm University, Roslagstullsbacken 21, 106 91 Stockholm, Sweden.,Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Gareth W Richings
- Department of Chemistry and Centre for Scientific Computing, University of Warwick, CV4 7AL Coventry, U.K
| | - Tony Hansson
- Department of Physics, AlbaNova University Centre, Stockholm University, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| | - Graham Worth
- Department of Chemistry, University College London, 20 Gordon Street, WC1H 0AJ London, U.K
| | - Richard D Thomas
- Department of Physics, AlbaNova University Centre, Stockholm University, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
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4
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Neville SP, Mirmiran A, Worth GA, Schuurman MS. Electron transfer in photoexcited pyrrole dimers. J Chem Phys 2019; 151:164304. [PMID: 31675891 DOI: 10.1063/1.5120006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Following on from previous experimental and theoretical work [Neville et al., Nat. Commun. 7, 11357 (2016)], we report the results of a combined electronic structure theory and quantum dynamics study of the excited state dynamics of the pyrrole dimer following excitation to its first two excited states. Employing an exciton-based analysis of the Ã(π3s/σ*) and B̃(π3s/3p/σ*) states, we identify an excited-state electron transfer pathway involving the coupling of the Ã(π3s/σ*) and B̃(π3s/3p/σ*) states and driven by N-H dissociation in the B̃(π3s/3p/σ*) state. This electron transfer mechanism is found to be mediated by vibronic coupling of the B̃ state, which has a mixed π3s/3p Rydberg character at the Franck-Condon point, to a high-lying charge transfer state of the πσ* character by the N-H stretch coordinate. Motivated by these results, quantum dynamics simulations of the excited-state dynamics of the pyrrole dimer are performed using the multiconfigurational time-dependent Hartree method and a newly developed model Hamiltonian. It is predicted that the newly identified electron transfer pathway will be open following excitation to both the Ã(π3s/σ*) and B̃(π3s/3p/σ*) states and may be the dominant relaxation pathway in the latter case.
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Affiliation(s)
- Simon P Neville
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Adam Mirmiran
- National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Graham A Worth
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Michael S Schuurman
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
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5
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Lamas I, Longarte A, Peralta Conde A, Muga G, Townsend D, Montero R. Dynamics of Pyrroles Excited to the 3s/πσ* State. J Phys Chem A 2019; 123:8982-8993. [DOI: 10.1021/acs.jpca.9b06045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Iker Lamas
- Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao, Spain
| | - Asier Longarte
- Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao, Spain
| | - Alvaro Peralta Conde
- Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao, Spain
| | - Gonzalo Muga
- Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao, Spain
| | - Dave Townsend
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Raul Montero
- SGIKER Laser Facility, Universidad del País Vasco (UPV/EHU), 48940 Leioa, Spain
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6
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León I, Fernández JA. Influence of the solvent in the electronic excitation of aromatic alcohols: Excited state IR-UV of propofol(H 2O) 8. J Chem Phys 2019; 150:214306. [PMID: 31176335 DOI: 10.1063/1.5093813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
It is well known that water plays an important role in the reactivity and dynamics in a solution of molecules in electronic excited states. For example, electronic excitation is usually accompanied by a solvent rearrangement that may also influence the redistribution of the excitation energy. However, there is a lack of experimental data on such processes. Here, we explore the structural changes that follow electronic excitation in aggregates of propofol (2,6-diisopropylphenol) with up to eight water molecules, using a combination of mass-resolved excitation spectroscopy and density functional theory calculations. The molecules of water form a polyhedron around the hydroxyl group of propofol, also interacting with the π cloud of the aromatic ring. Electronic excitation produces a strong structural change in the water superstructure, which moves to an interaction with one of the carbon atoms of the aromatic ring, producing its distortion into a prefulvenic structure. Such deformation is not observed in smaller water clusters or in propofol-phenol aggregates highlighting the decisive role played by the solvent.
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Affiliation(s)
- Iker León
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV-EHU), Barrio Sarriena S/N, Leioa 48940, Spain
| | - José A Fernández
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV-EHU), Barrio Sarriena S/N, Leioa 48940, Spain
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7
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Montero R, Lamas I, León I, Fernández JA, Longarte A. Excited state dynamics of aniline homoclusters. Phys Chem Chem Phys 2019; 21:3098-3105. [PMID: 30672912 DOI: 10.1039/c8cp06416d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have investigated the relaxation, following excitation in the 290-235 nm region, of neutral aniline homoclusters (An)n formed in a supersonic expansion by femtosecond time resolved ionization. The applied method permits isolation of the dynamics of the dimer from that originated in bigger species of the generated distribution. Interestingly, and differently from the monomer and (An)n≥3 clusters, the dimer does not present a N-H dissociative 1πσ* channel. This fact can be explained in terms of the symmetric structure adopted, in which each molecule establishes two N-Hπ interactions, destabilizing the H dissociation channel. The observations permit relating the photophysics to the interactions established by the aniline units and confirming previous observations and theoretical predictions on the structure of aniline aggregates.
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Affiliation(s)
- Raúl Montero
- SGIker Laser Facility, UPV/EHU, Sarriena, s/n, Leioa 48940, Spain
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8
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Fielding HH, Worth GA. Using time-resolved photoelectron spectroscopy to unravel the electronic relaxation dynamics of photoexcited molecules. Chem Soc Rev 2018; 47:309-321. [PMID: 29168864 DOI: 10.1039/c7cs00627f] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved photoelectron spectroscopy measurements combined with quantum chemistry and dynamics calculations allow unprecedented insight into the electronic relaxation mechanisms of photoexcited molecules in the gas-phase. In this Tutorial Review, we explain the essential concepts linking photoelectron spectroscopy measurements with electronic structure and how key features on the potential energy landscape are identified using quantum chemistry and quantum dynamics calculations. We illustrate how time-resolved photoelectron spectroscopy and theory work together using examples ranging in complexity from the prototypical organic molecule benzene to a pyrrole dimer bound by a weak N-Hπ interaction and the green fluorescent protein chromophore.
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Affiliation(s)
- Helen H Fielding
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
| | - Graham A Worth
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
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9
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Cole-Filipiak NC, Staniforth M, d. N. Rodrigues N, Peperstraete Y, Stavros VG. Ultrafast Dissociation Dynamics of 2-Ethylpyrrole. J Phys Chem A 2017; 121:969-976. [DOI: 10.1021/acs.jpca.6b12228] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Neil C. Cole-Filipiak
- Department
of Chemistry, University of Warwick, Library Road, Coventry CV4 7AL, United Kingdom
| | - Michael Staniforth
- Department
of Chemistry, University of Warwick, Library Road, Coventry CV4 7AL, United Kingdom
- Department
of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
| | | | - Yoann Peperstraete
- AILES
beamline, L’Orme des Merisiers, Synchrotron SOLEIL, Saint Aubin, BP 48, 91192 Gif sur Yvette Cedex, France
| | - Vasilios G. Stavros
- Department
of Chemistry, University of Warwick, Library Road, Coventry CV4 7AL, United Kingdom
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