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Lopes Jesus AJ, de Lucena Júnior JR, Fausto R, Reva I. Infrared Spectra and Phototransformations of meta-Fluorophenol Isolated in Argon and Nitrogen Matrices. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238248. [PMID: 36500356 PMCID: PMC9735537 DOI: 10.3390/molecules27238248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022]
Abstract
Monomers of meta-fluorophenol (mFP) were trapped from the gas phase into cryogenic argon and nitrogen matrices. The estimated relative energies of the two conformers are very close, and in the gas phase they have nearly equal populations. Due to the similarity of their structures (they only differ in the orientation of the OH group), the two conformers have also similar predicted vibrational signatures, which makes the vibrational characterization of the individual rotamers challenging. In the present work, it has been established that in an argon matrix only the most stable trans conformer of mFP exists (the OH group pointing away from the fluorine atom). On the other hand, the IR spectrum of mFP in a nitrogen matrix testifies to the simultaneous presence in this matrix of both the trans conformer and of the higher-energy cis conformer (the OH group pointing toward the fluorine atom), which is stabilized by interaction with the matrix gas host. We found that the exposition of the cryogenic N2 matrix to the Globar source of the infrared spectrometer affects the conformational populations. By collecting experimental spectra, either in the full mid-infrared range or only in the range below 2200 cm-1, we were able to reliably distinguish two sets of experimental bands originating from individual conformers. A comparison of the two sets of experimental bands with computed infrared spectra of the conformers allowed, for the first time, the unequivocal vibrational identification of each of them. The joint implementation of computational vibrational spectroscopy and matrix-isolation infrared spectroscopy proved to be a very accurate method of structural analysis. Some mechanistic insights into conformational isomerism (the quantum tunneling of hydrogen atom and vibrationally-induced conformational transformations) have been addressed. Finally, we also subjected matrix-isolated mFP to irradiations with UV light, and the phototransformations observed in these experiments are also described.
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Affiliation(s)
- A. J. Lopes Jesus
- CQC-IMS, Faculty of Pharmacy, University of Coimbra, 3004-295 Coimbra, Portugal
- Correspondence: (A.J.L.J.); (I.R.)
| | | | - Rui Fausto
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Igor Reva
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
- CIEPQPF, Department of Chemical Engineering, University of Coimbra, 3030-790 Coimbra, Portugal
- Correspondence: (A.J.L.J.); (I.R.)
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2
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Dupont J, Guillot R, Lepère V, Zehnacker A. Jet-cooled laser spectroscopy and solid-state vibrational circular dichroism of the cyclo-(Tyr-Phe) diketopiperazine dipeptide. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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3
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Tzeng SY, Takahashi K, Tzeng WB. Two-Color Resonant Two-Photon Mass-Analyzed Threshold Ionization of 2,4-Difluoroanisole and the Additivity Relation of Ionization Energy. J Phys Chem A 2020; 124:10517-10526. [DOI: 10.1021/acs.jpca.0c08272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sheng Yuan Tzeng
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, 1 Section 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Kaito Takahashi
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, 1 Section 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Wen Bih Tzeng
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, 1 Section 4, Roosevelt Road, Taipei 10617, Taiwan
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4
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Cooper GA, Cobbin MR, Ashfold MNR. Effects of Ring Fluorination on the Ultraviolet Photodissociation Dynamics of Phenol. J Phys Chem A 2020; 124:9698-9709. [PMID: 33179506 DOI: 10.1021/acs.jpca.0c08927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dynamics of photoinduced O-H bond fission in five fluorinated phenols (2-fluorophenol, 3-fluorophenol, 2,6-difluorophenol, 3,4,5-trifluorophenol, and pentafluorophenol) have been investigated by H Rydberg atom photofragment translational spectroscopy following excitation at many wavelengths in the range 220 ≤ λ ≤ 275 nm. The presence of multiple fluorine substituents reduces the efficiency of O-H bond fission (by tunneling) from the first excited (11ππ*) electronic state, whereas all bar the perfluorinated species undergo O-H bond fission when excited at shorter wavelengths (to the 21ππ* state). As in bare phenol, O-H bond fission is deduced to occur by non-adiabatic coupling at conical intersections between the photoprepared "bright" ππ* states and the 11πσ* potential energy surface. In all cases, the fluorophenoxyl photoproducts are found to be formed in a range of vibrational levels, all of which include an odd number of quanta (typically one) in an out-of-plane (a″) vibrational mode; this product vibration is viewed as a legacy of the parent out-of-plane motions that promote non-adiabatic coupling to the dissociative 11πσ* potential. The radical products also show activity in in-plane vibrations involving coupled (both in- and out-of-phase) C-O and C-F wagging motions, which can be traced to the impulse between the recoiling O and H atoms and, in detail, are sensitive to the presence (or not) of an intramolecular F···H-O hydrogen bond. Upper limit values for the O-H bond dissociation energies are reported for all molecules studied apart from pentafluorophenol.
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Affiliation(s)
- Graham A Cooper
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
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Backler F, Wang F. Switching On/Off the Intramolecular Hydrogen Bonding of 2-Methoxyphenol Conformers: An NMR Study. Aust J Chem 2020. [DOI: 10.1071/ch19600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Intramolecular hydrogen bonding of 2-methoxyphenol (2-MP, guaiacol) is studied using NMR spectroscopy combined with quantum mechanical density functional theory (DFT) calculations. The hydrogen bonding of OH⋯O and HO⋯H is switched on in the conformers of anti–syn (AS, 99.64% dominance) and anti–gauche (AG), respectively, with respect to the anti–anti (AA) conformer (without either such hydrogen bonding interactions). It confirms that the 13C and 1H NMR chemical shift of AS dominates the measured NMR spectra, as the AS conformer reproduces the measurements in CDCl3 solvent (RMSD of 1.86ppm for 13C NMR and of 0.27ppm for 1H NMR). The chemical shift of hydroxyl H(1) at 5.66 pm is identified as the fingerprint of the OH(1)⋯OCH3 hydrogen bonding in AS, as it exhibits a significant deshielding from H(1) of AA (4.24ppm) and H(1) of AG (4.38ppm) without such OH(1)⋯OCH3 hydrogen bonding. The AG conformer (C1 point group symmetry) possesses a less strong hydrogen bonding of HO⋯HCH2O, with the methoxyl group out of the aromatic phenol plane. The substituent effect of AG due to the resonance interaction of methoxyl being out of plane in a concentrated solution shifts the ortho- and para-aromatic carbons, C(3)/C(5), of the AG to ~125.05/125.44ppm from the corresponding carbons in AS at 108.81/121.60ppm. The hydrogen bonding exhibits inwards reduction of IR frequency regions of AS and AG from AA. Finally, energy decomposition analysis (EDA) indicates that there is a steric energy of 45.01kcal mol−1 between the AS and AG when different intramolecular hydrogen bonding is switched on.
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6
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Zhang B. Unraveling vibrational wavepacket dynamics using femtosecond ion yield spectroscopy and photoelectron imaging. CHINESE J CHEM PHYS 2019. [DOI: 10.1063/1674-0068/cjcp1811252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Bing Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
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7
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Kenjo S, Iida Y, Chaki N, Kinoshita SN, Inokuchi Y, Yamazaki K, Ebata T. Laser spectroscopic study on sinapic acid and its hydrated complex in a cold gas phase molecular beam. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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8
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Islam S, Ganesan A, Auchettl R, Plekan O, Acres RG, Wang F, Prince KC. Electronic structure and intramolecular interactions in three methoxyphenol isomers. J Chem Phys 2018; 149:134312. [DOI: 10.1063/1.5048691] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Shawkat Islam
- Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, School of Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
| | - Aravindhan Ganesan
- Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, School of Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
| | - Rebecca Auchettl
- Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, School of Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
| | - Oksana Plekan
- Elettra Sincrotrone Trieste, SS 14-km 163,5 in Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Robert G. Acres
- Elettra Sincrotrone Trieste, SS 14-km 163,5 in Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Feng Wang
- Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, School of Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
| | - Kevin C. Prince
- Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, School of Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- Elettra Sincrotrone Trieste, SS 14-km 163,5 in Area Science Park, 34149 Basovizza, Trieste, Italy
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9
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Femtosecond time-resolved observation of butterfly vibration in electronically excited o-fluorophenol. Sci Rep 2017; 7:15362. [PMID: 29127301 PMCID: PMC5681578 DOI: 10.1038/s41598-017-14483-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 10/11/2017] [Indexed: 11/24/2022] Open
Abstract
The butterfly vibration during the hydrogen tunneling process in electronically excited o-fluorophenol has been visualized in real time by femtosecond time-resolved ion yield spectroscopy coupled with time-resolved photoelectron imaging technique. A coherent superposition of out-of-plane C–F butterfly motions is prepared in the first excited electronic state (S1). As the C–F bond vibrates with respect to the aromatic ring, the nuclear geometry varies periodically, leading to the corresponding variation in the photoionization channel. By virtue of the more favorable ionization probability from the nonplanar minimum via resonance with the Rydberg states, the evolution of the vibrational wave packet is manifested as a superimposed beat in the parent-ion transient. Moreover, time-resolved photoelectron spectra offer a direct mapping of the oscillating butterfly vibration between the planar geometry and nonplanar minimum. The beats for the photoelectron peaks originating from the planar geometry are out of phase with those from the nonplanar minimum. Our results provide a physically intuitive and complete picture of the oscillatory flow of energy responsible for the coherent vibrational motion on the excited state surface.
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10
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Wilke M, Schneider M, Wilke J, Ruiz-Santoyo JA, Campos-Amador JJ, González-Medina ME, Álvarez-Valtierra L, Schmitt M. Rotationally resolved electronic spectroscopy study of the conformational space of 3-methoxyphenol. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.10.096] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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11
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Chatterjee P, Ghosh AK, Chakraborty T. Hydrogen bond induced HF elimination from photoionized fluorophenol dimers in the gas phase. J Chem Phys 2017; 146:084310. [DOI: 10.1063/1.4976988] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Piyali Chatterjee
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A Raja S C Mullick Road, Jadavpur, Kolkata 700032, India
| | - Arup K. Ghosh
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A Raja S C Mullick Road, Jadavpur, Kolkata 700032, India
| | - Tapas Chakraborty
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A Raja S C Mullick Road, Jadavpur, Kolkata 700032, India
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12
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Banerjee P, Mukhopadhyay DP, Chakraborty T. On the origin of donor O-H bond weakening in phenol-water complexes. J Chem Phys 2016; 143:204306. [PMID: 26627958 DOI: 10.1063/1.4936208] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Matrix isolation infrared spectroscopy has been used to investigate intermolecular interactions in a series of binary O-H⋯O hydrogen bonded phenol-water complexes where water is the common acceptor. The interaction at the binding site has been tuned by incorporating multiple fluorine substitutions at different aromatic ring sites of the phenol moiety. The spectral effects for the aforesaid chemical changes are manifested in the infrared spectra of the complexes as systematic increase in spectral shift of the phenolic O-H stretching fundamental (ΔνO-H). While νO-H bands of the monomers of all the fluorophenols appear within a very narrow frequency range, the increase in ΔνO-H of the complexes from phenol to pentafluorophenol is very large, nearly 90%. The observed values of ΔνO-H do not show a linear correlation with the total binding energies (ΔEb) of the complexes, expected according to Badger-Bauer rule. However, in the same ΔνO-H vs ΔEb plot, nice linear correlations are revealed if the complexes of ortho-fluorophenols are treated separately from their meta/para-substituted analogues. The observations imply that in spite of having the same binding site (O-H⋯O) and the same chemical identities (phenolic), the complexes of ortho and non-ortho fluorophenols do not belong, from the viewpoint of detailed molecular interactions, to a homologous series. Linear correlations of ΔνO-H are, however, observed with respect to the electrostatic component of ΔEb as well as the quantum mechanical charge transfer interaction energy (ECT). From quantitative viewpoint, the latter correlation along with the associated electronic structure parameters appears more satisfactory. It has also been noted that the observed ΔνO-H values of the complexes display a linear relationship with the aqueous phase pKa values of the respective phenol derivatives.
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Affiliation(s)
- Pujarini Banerjee
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Deb Pratim Mukhopadhyay
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Tapas Chakraborty
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Kolkata 700032, India
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13
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Zhang L, Liu S, Cheng M, Du Y, Zhu Q. Vibrational Spectra and Theoretical Calculations of cis- and trans-3-Fluoro-N-methylaniline in the Neutral (S(0)) and Cationic (D(0)) Ground States. J Phys Chem A 2016; 120:81-94. [PMID: 26669268 DOI: 10.1021/acs.jpca.5b11991] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mass-analyzed threshold ionization spectra of jet-cooled cis- and trans-3-fluoro-N-methylaniline (3FNMA) were recorded by ionizing via the vibrationless 0(0) and various vibrational levels of the S1 state. The adiabatic ionization energies of cis- and trans-3FNMA are determined to be 61,742 ± 5 and 61,602 ± 5 cm(-1), respectively. In the 0-1800 cm(-1) region, most of the observed vibrations in the D0 state result from the in-plane ring deformation and substituent-sensitive modes. For the high-frequency vibration region, the infrared-ultraviolet double-resonance and autoionization-detected infrared spectroscopies were applied to investigate the N-H and C-H stretching vibrations of bare 3FNMA in the S0 and D0 states. The C-H stretching vibrational information, which we failed to obtain for the bare 3FNMA cation, is complemented by recording the infrared-photodissociation spectra of its Ar cluster cation. It is revealed that a red-shifted frequency and an enhanced intensity are observed for the N-H stretch, while blue-shifted frequencies and greatly decreased intensities are found for both aromatic and the methyl C-H stretches. The blue shift of the C-H stretches is first explained by the balance of two factors, namely, the hyperconjugative interaction and the rehybridization effect. Analysis of the vibrational frequencies reveals a correlation between the relative stability of two rotamers in different electronic states and the relative rigidity of aromatic ring, indicating a mechanism of the long-range interactions "through bond" between the substituents. The density functional theory calculations can well reproduce the vibrational spectra in both S0 and D0 states. With the experimental and theoretical data, the substitution and conformation effects on the properties of 3FNMA in the S0 and D0 states, including the molecular structures, the reactive sites of electrophilic attack, and the vibrational behaviors, were discussed in detail.
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Affiliation(s)
- Lijuan Zhang
- Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China.,Department of Chemical Engineering, Binzhou University , Binzhou 256600, Shandong, P. R. China
| | - Sheng Liu
- Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China
| | - Min Cheng
- Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China
| | - Yikui Du
- Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China
| | - Qihe Zhu
- Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China
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14
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Biswal HS, Bhattacharyya S, Bhattacherjee A, Wategaonkar S. Nature and strength of sulfur-centred hydrogen bonds: laser spectroscopic investigations in the gas phase and quantum-chemical calculations. INT REV PHYS CHEM 2015. [DOI: 10.1080/0144235x.2015.1022946] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Miyazaki M, Yoshikawa S, Michels F, Misawa K, Ishiuchi SI, Sakai M, Dopfer O, Müller-Dethlefs K, Fujii M. Mass analyzed threshold ionization detected infrared spectroscopy: isomerization activity of the phenol–Ar cluster near the ionization threshold. Phys Chem Chem Phys 2015; 17:2494-503. [DOI: 10.1039/c4cp04584j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new spectroscopic method reveals the barrier and the crucial role of direct photoionization in the π → H site switching in phenol–Ar.
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Affiliation(s)
- Mitsuhiko Miyazaki
- Chemical Resources Laboratory
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
| | - Shunpei Yoshikawa
- Chemical Resources Laboratory
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
| | - François Michels
- The Photon Science Institute and School of Chemistry
- The University of Manchester
- Manchester
- UK
| | - Kentaro Misawa
- Chemical Resources Laboratory
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
| | - Shun-ichi Ishiuchi
- Chemical Resources Laboratory
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
| | - Makoto Sakai
- Chemical Resources Laboratory
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
| | - Otto Dopfer
- Institut für Optik und Atomare Physik
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - Klaus Müller-Dethlefs
- The Photon Science Institute and School of Chemistry
- The University of Manchester
- Manchester
- UK
| | - Masaaki Fujii
- Chemical Resources Laboratory
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
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16
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Young JD, Staniforth M, Dean JC, Roberts GM, Mazzoni F, Karsili TNV, Ashfold MNR, Zwier TS, Stavros VG. Towards Understanding Photodegradation Pathways in Lignins: The Role of Intramolecular Hydrogen Bonding in Excited States. J Phys Chem Lett 2014; 5:2138-2143. [PMID: 26270505 DOI: 10.1021/jz500895w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The photoinduced dynamics of the lignin building blocks syringol, guaiacol, and phenol were studied using time-resolved ion yield spectroscopy and velocity map ion imaging. Following irradiation of syringol and guaiacol with a broad-band femtosecond ultraviolet laser pulse, a coherent superposition of out-of-plane OH torsion and/or OMe torsion/flapping motions is created in the first excited (1)ππ* (S1) state, resulting in a vibrational wavepacket, which is probed by virtue of a dramatic nonplanar → planar geometry change upon photoionization from S1 to the ground state of the cation (D0). Any similar quantum beat pattern is absent in phenol. In syringol, the nonplanar geometry in S1 is pronounced enough to reduce the degree of intramolecular H bonding (between OH and OMe groups), enabling H atom elimination from the OH group. For guaiacol, H bonding is preserved after excitation, despite the nonplanar geometry in S1, and prevents O-H bond fission. This behavior affects the propensities for forming undesired phenoxyl radical sites in these three lignin chromophores and provides important insight into their relative "photostabilities" within the larger biopolymer.
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Affiliation(s)
- Jamie D Young
- †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
| | - Jacob C Dean
- §Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Gareth M Roberts
- †Department of Chemistry, University of Warwick, Library Road, Coventry CV4 7AL, United Kingdom
| | - Federico Mazzoni
- ‡Lens, Polo Scientifico e Tecnologico dell'Universitá di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino, Florence, Italy
- ⊥Dipartimento di Chemica, Polo Scientifico e Tecnologico dell'Universitá di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
| | - Tolga N V Karsili
- #School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Michael N R Ashfold
- #School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Timothy S Zwier
- §Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Vasilios G Stavros
- †Department of Chemistry, University of Warwick, Library Road, Coventry CV4 7AL, United Kingdom
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17
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Dean JC, Navotnaya P, Parobek AP, Clayton RM, Zwier TS. Ultraviolet spectroscopy of fundamental lignin subunits: guaiacol, 4-methylguaiacol, syringol, and 4-methylsyringol. J Chem Phys 2014; 139:144313. [PMID: 24116625 DOI: 10.1063/1.4824019] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ultraviolet spectroscopy of the G- and S-type lignin subunits, guaiacol (G) and syringol (S), along with their para-methylated derivatives 4-methylguaiacol (4-MG) and 4-methylsyringol (4-MS), has been carried out in the cold, isolated environment of a supersonic jet. The excitation spectra and dispersed fluorescence (DFL) spectra of G and 4-MG show strong S0-S1 origins and Franck-Condon activity involving both the ring modes typical of aromatic derivatives, and the four lowest frequency out-of-plane modes (a") and lowest in-plane mode (a') involving the OH and OCH3 groups. The four low-frequency out-of-plane modes undergo extensive Duschinsky mixing between the ground and excited state. In 4-MG, combination bands involving methyl rotor levels with out-of-plane modes appeared with surprisingly high intensity, indicating a high degree of hindered rotor-vibration coupling in both S0 and S1. These mixing effects accompany the change in geometry upon π-π∗ electronic excitation going from a planar ground state to a non-planar excited state. Time-dependent density functional theory (TDDFT M05-2X∕6-311++G(d,p)) calculations predict a geometric distortion along the out-of-plane oxygen flapping coordinate, yielding a double minimum potential in S1 with a barrier to planarity of 195 cm(-1) in G. The excitation spectrum of S and 4-MS showed a much higher degree of spectral congestion and a larger geometry change evident by a shifted intensity distribution peaking ∼300 cm(-1) above the electronic origin. TDDFT calculations predict a larger geometry change in S compared with G, with the OH and H-bonded methoxy groups displaced in opposite directions above∕below the ring plane. Dispersed fluorescence from all S1 excited state levels in S∕4-MS yield only broad emission peaking far to the red of the excitation wavelength (-4500 cm(-1)). Several hypotheses regarding the source of this broad, redshifted emission were tested, but the cause remains unclear. p-Methylation was found to significantly redshift the UV absorption in both 4-MG and 4-MS, and methyl rotor transitions were assigned in both allowing for the determination of the shape and barrier heights of their respective potentials. These results provide a foundation for the discrimination of G- and S-chromophores in lignin oligomers, and demonstrate the potential for site-selective absorption.
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Affiliation(s)
- Jacob C Dean
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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18
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Shivatare V, Tzeng WB. Spectroscopic Investigation of cis-2,4-Difluorophenol Cation by Mass-analyzed Threshold Ionization Spectroscopy. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.3.815] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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19
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Miyazaki M, Takeda A, Schmies M, Sakai M, Misawa K, Ishiuchi SI, Michels F, Müller-Dethlefs K, Dopfer O, Fujii M. Ionization-induced π → H site-switching in phenol–CH4complexes studied using IR dip spectroscopy. Phys Chem Chem Phys 2014; 16:110-6. [DOI: 10.1039/c3cp53533a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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20
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Kierspel T, Horke DA, Chang YP, Küpper J. Spatially separated polar samples of the cis and trans conformers of 3-fluorophenol. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2013.11.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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21
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Dean JC, Walsh PS, Biswas B, Ramachandran PV, Zwier TS. Single-conformation UV and IR spectroscopy of model G-type lignin dilignols: the β–O–4 and β–β linkages. Chem Sci 2014. [DOI: 10.1039/c3sc53260g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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22
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Gao R, Sun X, Yu W, Zhang Q, Wang W. Mechanism and rate constants for complete series reactions of 19 fluorophenols with atomic H. J Environ Sci (China) 2014; 26:154-159. [PMID: 24649701 DOI: 10.1016/s1001-0742(13)60392-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fluorine-containing halogenated fluorophenol may have effect as intermediate species involved in the formation of polyfluorinated dibenzo-p-dioxin/dibenzofurans (PFDDs/Fs). The mechanism for the atomic H initiated reactions with complete series of nineteen fluorophenol congeners was studies using the density functional theory. At the MPWB1K/6-31+G(d,p) level, the geometries and frequencies of reactants, transition states, and products were obtained, and the accurate energetic values were acquired at the MPWB1K/6-311+G(3df,2p) level. The rate constants were evaluated by the canonical variational transition-state theory with the small curvature tunneling contribution over a wide temperature range of 600-1000 K. The study shows that the intramolecular hydrogen-bond in the ortho-substituted FPs as well as the inductive effect of the electron-withdrawing fluorine and steric repulsion of multiple substitutions may ultimately be responsible for the relative strength of the O-H bonds in FPs. The results can be used for further studies on PFDD/Fs formation mechanism.
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Tsai CY, Tzeng WB. Rotamers of 3,4-difluorophenol studied by two-color resonant two-photon mass-analyzed threshold ionization spectroscopy. J Photochem Photobiol A Chem 2013. [DOI: 10.1016/j.jphotochem.2013.07.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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24
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Bhattacharyya S, Bhattacherjee A, Shirhatti PR, Wategaonkar S. O-H···S hydrogen bonds conform to the acid-base formalism. J Phys Chem A 2013; 117:8238-50. [PMID: 23947570 DOI: 10.1021/jp405414h] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydrogen bonding interaction between the ROH hydrogen bond donor and sulfur atom as an acceptor has not been as well characterized as the O-H···O interaction. The strength of O-H···O interactions for a given donor has been well documented to scale linearly with the proton affinity (PA) of the H-bond acceptor. In this regard, O-H···O interactions conform to the acid-base formalism. The importance of such correlation is to be able to estimate molecular property of the complex from the known thermodynamic data of its constituents. In this work, we investigate the properties of O-H···S interaction in the complexes of the H-bond donor and sulfur containing acceptors of varying proton affinity. The hydrogen bonded complexes of p-Fluorophenol (FP) with four different sulfur containing acceptors and their oxygen analogues, namely H2O/H2S, MeOH/MeSH, Me2O/Me2S and tetrahydrofuran (THF)/tetrahydrothiophene (THT) were characterized in regard to its S1-S0 excitation spectra and the IR spectra. Two-color resonantly enhanced multiphoton ionization (2c-R2PI), resonant ion-dip infrared (RIDIR) spectroscopy, and IR-UV hole burning spectroscopic techniques were used to probe the hydrogen bonds in the aforementioned complexes. The spectroscopic data along with the ab initio calculations were used to deduce the strength of the O-H···S hydrogen bonding interactions in these system relative to that in the O-H···O interactions. It was found that, despite being dominated by the dispersion interaction, the O-H···S interactions conform to the acid-base formalism as in the case of more conventional O-H···O interactions. The dissociation energies and the red shifts in the O-H stretching frequencies correlated very well with the proton affinity of the acceptors. However, the O-H···S interaction did not follow the same correlation as that in the O-H···O H-bond. The energy decomposition analysis showed that the dissociation energies and the red shifts in the O-H stretching frequencies follow a unified correlation if these two parameters were correlated with the sum of the charge transfer and the exchange component of the total binding energy.
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Affiliation(s)
- Surjendu Bhattacharyya
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
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25
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Fournier JA, Wolk AB, Johnson MA. Integration of cryogenic ion vibrational predissociation spectroscopy with a mass spectrometric interface to an electrochemical cell. Anal Chem 2013; 85:7339-44. [PMID: 23767985 DOI: 10.1021/ac401228y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cryogenic ion vibrational predissociation (CIVP) spectroscopy is used to structurally characterize electrochemically (EC)-generated oxidation products of the benchmark compound reserpine. Ionic products were isolated using EC-electrospray ionization (ESI) coupled to a 25 K ion trap prior to injection into a double-focusing, tandem time-of-flight photofragmentation mass spectrometer. Vibrational predissociation spectroscopy was carried out by photoevaporation of weakly bound N2 adducts over the range 800-3800 cm(-1) in a linear (i.e., single photon) action regime, thus enabling direct comparison of the experimental vibrational pattern with harmonic calculations. The locations of the NH and OH stretching fundamentals are most consistent with formation of 9-hydroxyreserpine, which is a different isomer than considered previously. This approach thus provides a powerful structural dimension for the analysis of electrochemical processes detected with the sensitivity of mass spectrometry.
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Affiliation(s)
- Joseph A Fournier
- Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520, United States
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26
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Xu Y, Tzeng SY, Zhang B, Tzeng WB. Rotamers of 3,4-difluoroanisole studied by two-color resonant two-photon mass-analyzed threshold ionization spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 102:365-370. [PMID: 23220679 DOI: 10.1016/j.saa.2012.10.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 10/15/2012] [Indexed: 06/01/2023]
Abstract
We reported the vibronic and cation spectra of 3,4-difluoroanisole. The band origins of the S(1) ←S(0) electronic transition of the cis and trans rotamers appear at 35,505 ± 2 and 35,711 ± 2 cm(-1) and the adiabatic ionization energies are determined to be 67,780 ± 5 and 68,125 ± 5cm(-1), respectively. Most of the observed active vibrations in the electronically excited S(1) and cationic ground D(0) states mainly involve in-plane ring deformation and substituent-sensitive bending vibrations. Analysis of the obtained vibronic and cation spectra suggests that the molecular geometry, symmetry, and vibrational coordinates of the cation in the D(0) state are like those of the neutral species in the S(1) state for these two isomeric species.
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Affiliation(s)
- Yanqi Xu
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
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27
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Winter NOC, Graf NK, Leutwyler S, Hättig C. Benchmarks for 0–0 transitions of aromatic organic molecules: DFT/B3LYP, ADC(2), CC2, SOS-CC2 and SCS-CC2 compared to high-resolution gas-phase data. Phys Chem Chem Phys 2013; 15:6623-30. [DOI: 10.1039/c2cp42694c] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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28
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Shiung KS, Yu D, Tzeng SY, Tzeng WB. Cation spectroscopy of o-fluoroanisole and p-fluoroanisole by two-color resonant two-photon mass-analyzed threshold ionization. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2011.12.055] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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29
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Rodrigo CP, James WH, Zwier TS. Single-conformation ultraviolet and infrared spectra of jet-cooled monolignols: p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol. J Am Chem Soc 2011; 133:2632-41. [PMID: 21294542 DOI: 10.1021/ja109218j] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Single-conformation spectroscopy of the three lignin monomers (hereafter "monolignols") p-coumaryl alcohol (pCoumA), coniferyl alcohol (ConA), and sinapyl alcohol (SinA) has been carried out on the isolated molecules cooled in a supersonic expansion. Laser-induced fluorescence excitation, dispersed fluorescence, resonant two-photon ionization, UV-UV hole-burning, and resonant ion-dip infrared spectroscopy were carried out as needed to obtain firm assignments for the observed conformers of the three molecules. In each case, two conformers were observed, differing in the relative orientations of the vinyl and OH substituents para to one another on the phenyl ring. In pCoumA, the two conformers have S(0)-S(1) origins nearly identical in size, split from one another by only 7 cm(-1), in close analogy with previous results of Morgan et al. on p-vinylphenol ( Chem. Phys. 2008 , 347 , 340 ). ConA, with its methoxy group ortho to the OH group, also has two low-energy conformers forming a syn/anti pair, in this case with the OH group locked into an orientation in which it forms an intramolecular H-bond with the adjacent methoxy group. The electronic frequency shift between the two conformers is dramatically increased to 805 cm(-1), with the dominant conformer of ConA (with S(0)-S(1) origin at 32 640 cm(-1)) about 5 times the intensity of its minor counterpart (with S(0)-S(1) origin at 33 444 cm(-1)). The presence of an OH···OCH(3) intramolecular H-bond is established by the shift of the OH stretch fundamental of the OH group to 3599 cm(-1), as it is in o-methoxyphenol ( Fujimaki et al. J. Chem. Phys. 1999 , 110 , 4238 ). Analogous single-conformation UV and IR spectra of o-methoxy-p-vinylphenol show a close similarity to ConA and provide a basis for a firm assignment of the red-shifted (blue-shifted) conformer of both molecules to the syn (anti) conformer. The two observed conformers of SinA, with its two methoxy group straddling the OH group, have S(0)-S(1) origins split by 239 cm(-1) (33 055 and 33 294 cm(-1)), a value between those in pCoumA and ConA. A combination of experimental data and calculations on the three monolignols and simpler derivatives is used to establish that the conformational preferences of the monolignols reflect the preferences of each of the ring substituents separately, enhanced by the presence of the intramolecular OH···OCH(3) H-bond. Taken as a whole, the presence of multiple flexible substituents locks in certain preferred orientations of the groups relative to one another, even in the apparently flexible allyl alcohol side chain (-CH═CH-CH(2)OH), where the OH group orients itself so that the hydrogen is pointed back over the vinyl π cloud in order to minimize interactions between the oxygen lone pairs and the π electrons.
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Affiliation(s)
- Chirantha P Rodrigo
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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30
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Pino GA, Oldani AN, Marceca E, Fujii M, Ishiuchi SI, Miyazaki M, Broquier M, Dedonder C, Jouvet C. Excited state hydrogen transfer dynamics in substituted phenols and their complexes with ammonia: ππ∗-πσ∗ energy gap propensity and ortho-substitution effect. J Chem Phys 2010; 133:124313. [DOI: 10.1063/1.3480396] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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31
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Watanabe H, Ishiuchi SI, Misawa K, Miyazaki M, Woodward JR, Fujii M. Measurement of adiabatic ionization energies of the rotational isomers of n-propylbenzene and m-fluorophenol by direct VUV laser photoionization. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2009.12.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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32
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Cocinero EJ, Lesarri A, Écija P, Grabow JU, Fernández JA, Castaño F. Conformational equilibria in vanillin and ethylvanillin. Phys Chem Chem Phys 2010; 12:12486-93. [DOI: 10.1039/c0cp00585a] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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Baquero EE, James WH, Choi TH, Jordan KD, Zwier TS. Single Conformation Spectroscopy of a Flexible Bichromophore: 3-(4-Hydroxyphenyl)-N-benzylpropionamide. J Phys Chem A 2008; 112:11115-23. [DOI: 10.1021/jp806787p] [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)
- Esteban E. Baquero
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, and Department of Chemistry, Chevron Science Center, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260
| | - William H. James
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, and Department of Chemistry, Chevron Science Center, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260
| | - Tae Hoon Choi
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, and Department of Chemistry, Chevron Science Center, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260
| | - Kenneth D. Jordan
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, and Department of Chemistry, Chevron Science Center, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260
| | - Timothy S. Zwier
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, and Department of Chemistry, Chevron Science Center, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260
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Huang J, Huang K, Liu S, Luo Q, Tzeng W. Vibrational spectra and theoretical calculations of p-chlorophenol in the electronically excited S1 and ionic ground D0 states. J Photochem Photobiol A Chem 2008. [DOI: 10.1016/j.jphotochem.2007.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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36
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Banerjee S, Chakraborty S, Parui PP, Nath D, Chakraborty T, Chowdhury M. Identification of two conformers of 5-indanol in a supersonic free jet. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.05.063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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37
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Yuan L, Li C, Lin JL, Yang SC, Tzeng WB. Mass analyzed threshold ionization spectroscopy of o-fluorophenol and o-methoxyphenol cations and influence of the nature and relative location of substituents. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2005.10.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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38
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Zhang L, Peslherbe GH, Muchall HM. Ultraviolet Absorption Spectra of Substituted Phenols: A Computational Study†. Photochem Photobiol 2006; 82:324-31. [PMID: 16313201 DOI: 10.1562/2005-07-08-ra-605] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Vertical excitation energies for electronic transitions from the ground state to the first two excited states of phenol, mono- and disubstituted methoxyphenols and methyl-substituted phenols have been characterized with the Time-Dependent Density Functional Theory (TD-DFT), the Complete Active Space Self-Consistent Field method (CASSCF) and the Coupled Cluster with Single and Double Excitations Equation-of-Motion approach (CCSD-EOM) to simulate and interpret experimental ultraviolet absorption spectra. While CASSCF excitation energies for the first two transitions either are grossly overestimated or exhibit a weak correlation with experimental data, both TD-DFT and CCSD-EOM perform very well, reproducing the spectral shifts of both the primary band and secondary band observed upon substitution. The conformational dependence of the calculated excitation energies is generally smaller than the shifts caused by substitution.
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Affiliation(s)
- Lei Zhang
- Centre for Research in Molecular Modeling and Department of Chemistry and Biochemistry, Concordia University, Montréal, Canada H4B 1R6
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39
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Riyad YM, Naumov S, Hermann R, Brede O. Deactivation of the first excited singlet state of thiophenols. Phys Chem Chem Phys 2006; 8:1697-706. [PMID: 16633654 DOI: 10.1039/b516924k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
On the bases of picosecond and nanosecond laser flash photolysis with detection by emission and absorption spectroscopy, a quantitative description is given of all deactivation channels of the first excited singlet state of thiophenols ArSH(S(1)) such as fluorescence, intersystem crossing (ISC), chemical dissociation into radicals, and radiation-less internal conversion (IC). For this purpose, the photolysis of thiophenol and its methyl-, methoxy-, and chloro-substituted derivatives was studied in solvents of increasing polarity: 1-chlorobutane, ethanol, and acetonitrile. The fluorescence lifetime of the thiophenols was found to range from some hundreds of picoseconds up to a few nanoseconds, correlating with fluorescence quantum yields between 0.001-0.040, at room temperature. Depending on the substitution pattern of the aromatic ring, the quantum yield of the S-H bond dissociation was found to be between 0.3-0.5, irrespective of the solvent polarity. In laser photolysis, no triplet formation of the investigated compounds could be observed neither by the direct way nor by subsequent sensitization with beta-carotene. As a difference to the total, the radiation-less internal conversion (Phi(IC)>or= 0.5) was found to be the dominating process.
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Affiliation(s)
- Yasser M Riyad
- University of Leipzig, Interdisciplinary Group Time-Resolved Spectroscopy, Permoserstr. 15, D-4303, Leipzig, Germany
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40
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Yuan LW, Li C, Tzeng WB. Site-specific H/D exchange of p-methoxyphenol studied by resonant two-photon ionization and mass-analyzed threshold ionization spectroscopy. J Phys Chem A 2005; 109:9481-7. [PMID: 16866397 DOI: 10.1021/jp052850c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The origin of the S(1) <-- S(0) transition (E(1)) and the adiabatic ionization energy (IE) of cis-p-methoxyphenol-d(1)-OD are determined to be 33 660 and 62 302 cm(-1), whereas those of cis-p-methoxyphenol-d(1)-OCH(2)D are 33 669 and 62 323 cm(-1), respectively. Similarly, the E(1) and IE of trans-p-methoxyphenol-d(1)-OD are determined to be 33 563 and 62 191 cm(-1) and those of trans-p-methoxyphenol-d(1)-OCH(2)D are 33 575 and 62 216 cm(-1), respectively. Comparing these data with those of p-methoxyphenol suggests that the H/D exchange on the OH substituent gives rise to a red shift in both the E(1) and IE, whereas that on the OCH(3) group yields a blue shift. The mass-analyzed threshold ionization spectra of the selected isomers can be used as the fingerprints for molecular identification. Analysis of these cation spectra shows that the substituent-sensitive in-plane C-OH and C-OCH(3) bending (mode 9b) and breathing (mode 1) vibrations are active for all of these isomeric cations.
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Affiliation(s)
- L W Yuan
- Institute of Atomic and Molecular Sciences, Academia Sinica, P. O. Box 23-166, 1 Section 4, Roosevelt Road, Taipei 10617, Taiwan
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41
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Li C, Su H, Tzeng WB. Rotamers of p-methoxyphenol cation studied by mass analyzed threshold ionization spectroscopy. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.05.056] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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42
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Solca N, Dopfer O. Selective infrared photodissociation of protonated para-fluorophenol isomers: Substitution effects in oxonium and fluoronium ions. J Chem Phys 2004; 121:769-72. [PMID: 15260603 DOI: 10.1063/1.1756132] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Isomer-selective infrared photodissociation (IRPD) spectra are obtained for the first time for protonated polyfunctional aromatic molecules isolated in the gas phase. IRPD spectra of the oxonium and fluoronium isomers of protonated para-fluorophenol (C6H6FO+) were separately obtained by monitoring resonant photo-induced H2O and HF loss, respectively. Analysis of the F-H, O-H, and C-H stretch wave numbers provides valuable spectroscopic information on the chemical properties of these reactive intermediates, in particular on the substitution effects of functional groups.
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Affiliation(s)
- Nicola Solca
- Institute for Physical Chemistry, University of Wurzburg, Am Hubland, D-97074 Wurzburg, Germany
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43
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Zhang B, Li C, Su H, Lin JL, Tzeng WB. Mass analyzed threshold ionization spectroscopy of p-fluorophenol cation and the p-fluoro substitution effect. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.04.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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44
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Wu R, Brutschy B. Study on the structure and intra- and intermolecular hydrogen bonding of 2-methoxyphenol·(H2O)n (n=1,2). Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.04.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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45
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Honda M, Fujii A, Fujimaki E, Ebata T, Mikami N. NH Stretching Vibrations of Jet-Cooled Aniline and Its Derivatives in the Neutral and Cationic Ground States. J Phys Chem A 2003. [DOI: 10.1021/jp022504k] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Masahiro Honda
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Asuka Fujii
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Eiji Fujimaki
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Takayuki Ebata
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Naohiko Mikami
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
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46
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IR spectra of para-substituted phenol+–Ar cations: effect of halogenation on the intermolecular potential and O–H bond strength. Chem Phys Lett 2003. [DOI: 10.1016/s0009-2614(02)01929-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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47
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Ahn DS, Park SW, Lee S, Kim B. Effects of Substituting Group on the Hydrogen Bonding in Phenol−H2O Complexes: Ab Initio Study. J Phys Chem A 2002. [DOI: 10.1021/jp021519f] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Doo-Sik Ahn
- School of Environmental Science and Applied Chemistry, Kyunghee University, Kyungki-do 449-701, Korea
| | - Sung-Woo Park
- School of Environmental Science and Applied Chemistry, Kyunghee University, Kyungki-do 449-701, Korea
| | - Sungyul Lee
- School of Environmental Science and Applied Chemistry, Kyunghee University, Kyungki-do 449-701, Korea
| | - Bongsoo Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Taejon 305-701, Korea
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48
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Banerjee S, Guchhait N, Nath D, Chowdhury M, Meenakshi P, Wategaonkar S, Das A, Chakraborty T. Discrimination of two low-energy conformers of octahydroanthracene in supersonic jet. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(02)01570-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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49
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Fujii A, Ebata T, Mikami N. Direct Observation of Weak Hydrogen Bonds in Microsolvated Phenol: Infrared Spectroscopy of OH Stretching Vibrations of Phenol−CO and −CO2 in S0 and D0. J Phys Chem A 2002. [DOI: 10.1021/jp0212601] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Asuka Fujii
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Takayuki Ebata
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Naohiko Mikami
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
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Fujii A, Ebata T, Mikami N. An Infrared Study of π-Hydrogen Bonds in Micro-solvated Phenol: OH Stretching Vibrations of Phenol−X (X = C6H6, C2H4, and C2H2) Clusters in the Neutral and Cationic Ground States. J Phys Chem A 2002. [DOI: 10.1021/jp0208992] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Asuka Fujii
- Department of Chemistry, Graduate School of Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Takayuki Ebata
- Department of Chemistry, Graduate School of Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Naohiko Mikami
- Department of Chemistry, Graduate School of Sciences, Tohoku University, Sendai 980-8578, Japan
| |
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