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Roque JPL, Rosado MTS, Fausto R, Reva I. Dual Photochemistry of Benzimidazole. J Org Chem 2023; 88:2884-2897. [PMID: 36795993 PMCID: PMC9990075 DOI: 10.1021/acs.joc.2c02560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Monomers of benzimidazole trapped in an argon matrix at 15 K were characterized by vibrational spectroscopy and identified as 1H-tautomers exclusively. The photochemistry of matrix-isolated 1H-benzimidazole was induced by excitations with a frequency-tunable narrowband UV light and followed spectroscopically. Hitherto unobserved photoproducts were identified as 4H- and 6H-tautomers. Simultaneously, a family of photoproducts bearing the isocyano moiety was identified. Thereby, the photochemistry of benzimidazole was hypothesized to follow two reaction pathways: the fixed-ring and the ring-opening isomerizations. The former reaction channel results in the cleavage of the NH bond and formation of a benzimidazolyl radical and an H-atom. The latter reaction channel involves the cleavage of the five-membered ring and concomitant shift of the H-atom from the CH bond of the imidazole moiety to the neighboring NH group, leading to 2-isocyanoaniline and subsequently to the isocyanoanilinyl radical. The mechanistic analysis of the observed photochemistry suggests that detached H-atoms, in both cases, recombine with the benzimidazolyl or isocyanoanilinyl radicals, predominantly at the positions with the largest spin density (revealed using the natural bond analysis computations). The photochemistry of benzimidazole therefore occupies an intermediate position between the earlier studied prototype cases of indole and benzoxazole, which exhibit exclusively the fixed-ring and the ring-opening photochemistries, respectively.
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Affiliation(s)
- José P L Roque
- CQC-IMS, Department of Chemistry, University of Coimbra, Coimbra 3004-535, Portugal
| | - Mário T S Rosado
- CQC-IMS, Department of Chemistry, University of Coimbra, Coimbra 3004-535, Portugal
| | - Rui Fausto
- CQC-IMS, Department of Chemistry, University of Coimbra, Coimbra 3004-535, Portugal
| | - Igor Reva
- CQC-IMS, Department of Chemistry, University of Coimbra, Coimbra 3004-535, Portugal.,CIEPQPF, Department of Chemical Engineering, University of Coimbra, Coimbra 3030-790, Portugal
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2
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Structural changes of 1,2-diphenoxyethane upon electronic excitation from a combined Franck-Condon/rotational constants fit. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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3
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Structural changes of 1-(phenylethynyl)naphthalene upon electronic excitation from Franck–Condon fits of several fluorescence emission spectra. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.131910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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4
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Marlton SJP, McKinnon BI, Greißel P, Shiels OJ, Ucur B, Trevitt AJ. Picosecond excited-state lifetimes of protonated indazole and benzimidazole: The role of the N-N bond. J Chem Phys 2021; 155:184302. [PMID: 34773941 DOI: 10.1063/5.0071847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Certain chemical groups give rise to characteristic excited-state deactivation mechanisms. Here, we target the role of a protonated N-N chemical group in the excited-state deactivation of protonated indazole by comparison to its isomer that lacks this group, protonated benzimidazole. Gas-phase protonated indazole and protonated benzimidazole ions are investigated at room temperature using picosecond laser pump-probe photodissociation experiments in a linear ion-trap. Excited state lifetimes are measured across a range of pump energies (4.0-5.4 eV). The 1ππ* lifetimes of protonated indazole range from 390 ± 70 ps using 4.0 eV pump energy to ≤18 ps using 4.6 eV pump energy. The 1ππ* lifetimes of protonated benzimidazole are systematically longer, ranging from 3700 ± 1100 ps at 4.6 eV pump energy to 400 ± 200 ps at 5.4 eV. Based on these experimental results and accompanying quantum chemical calculations and potential energy surfaces, the shorter lifetimes of protonated indazole are attributed to πσ* state mediated elongation of the protonated N-N bond.
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Affiliation(s)
- Samuel J P Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Benjamin I McKinnon
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Phillip Greißel
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Boris Ucur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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5
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Structural changes upon electronic excitation in 1,3-dimethoxybenzene from Franck-Condon/rotational constants fits of the fluorescence emission spectra †. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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6
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Henrichs C, Zimmermann S, Hebestreit ML, Schmitt M. Excited state structure of isolated 2-cyanoindole and the binary 2-cyanoindole-(H2O)1 cluster from a combined Franck-Condon and rotational constants fit. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Excited state structure of isolated 4-cyanoindole from a combined Franck-Condon and rotational constants analysis†. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129241] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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8
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Structural changes upon electronic excitation in 1,2-dimethoxybenzene from rotationally resolved electronic spectroscopy of various isotopologues. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2019.01.074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Hebestreit ML, Schneider M, Lartian H, Betz V, Heinrich M, Lindic M, Choi MY, Schmitt M. Structures, dipole moments and excited state lifetime of isolated 4-cyanoindole in its ground and lowest electronically excited singlet states. Phys Chem Chem Phys 2019; 21:14766-14774. [PMID: 31222195 DOI: 10.1039/c9cp01618j] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The rotationally resolved electronic spectrum of 4-cyanoindole and some N-D and C-D deuterated isotopologues has been measured and analyzed. Dipole moments in the ground and electronically excited state have been determined, using electronic Stark spectroscopy. From the geometry changes upon excitation, orientation of the transition dipole moment, and the values for the permanent dipole moments, the lowest excited singlet state could be shown to be of La symmetry. The excited state lifetime of isolated 4-cyanoindole has been determined to be 11 ns, while for the ringdeuterated isotopologues lifetimes between 5 and 6 ns have been found. The different behavior of 3-, 4-, and 5-cyanoindole is discussed on the basis of the different electronic nature of the electronically excited singlet states.
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Affiliation(s)
- Marie-Luise Hebestreit
- Heinrich-Heine-Universität, Institut für Physikalische Chemie I, D-40225 Düsseldorf, Germany.
| | - Michael Schneider
- Heinrich-Heine-Universität, Institut für Physikalische Chemie I, D-40225 Düsseldorf, Germany.
| | - Hilda Lartian
- Heinrich-Heine-Universität, Institut für Physikalische Chemie I, D-40225 Düsseldorf, Germany.
| | - Vivienne Betz
- Heinrich-Heine-Universität, Institut für Physikalische Chemie I, D-40225 Düsseldorf, Germany.
| | - Michael Heinrich
- Heinrich-Heine-Universität, Institut für Physikalische Chemie I, D-40225 Düsseldorf, Germany.
| | - Mirko Lindic
- Heinrich-Heine-Universität, Institut für Physikalische Chemie I, D-40225 Düsseldorf, Germany.
| | - Myong Yong Choi
- Department of Chemistry (BK21+) and Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Michael Schmitt
- Heinrich-Heine-Universität, Institut für Physikalische Chemie I, D-40225 Düsseldorf, Germany.
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Wilke J, Wilke M, Brand C, Spiegel JD, Marian CM, Schmitt M. Modulation of the La/Lb Mixing in an Indole Derivative: A Position-Dependent Study Using 4-, 5-, and 6-Fluoroindole. J Phys Chem A 2017; 121:1597-1606. [DOI: 10.1021/acs.jpca.6b12605] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Josefin Wilke
- Institut
für Physikalische Chemie I, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - Martin Wilke
- Institut
für Physikalische Chemie I, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - Christian Brand
- Institut
für Physikalische Chemie I, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
- Faculty
of Physics, VCQ, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
| | - J. Dominik Spiegel
- Institut
für Theoretische Chemie und Computerchemie, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - Christel M. Marian
- Institut
für Theoretische Chemie und Computerchemie, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - Michael Schmitt
- Institut
für Physikalische Chemie I, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
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11
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Stuhlmann B, Gmerek F, Krügler D, Schmitt M. Determination of the geometry change of benzimidazole upon electronic excitation from a combined Franck–Condon/rotational constants fit. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2014.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Brand C, Rolf J, Wilke M, Schmitt M. High resolution electronic spectroscopy of vibrationally hot bands of benzimidazole. J Phys Chem A 2013; 117:12812-20. [PMID: 24261704 DOI: 10.1021/jp408755q] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Rotationally resolved electronic spectra of seven vibrationally excited bands in the electronic spectrum of benzimidazole have been measured and analyzed. From the vibrational contributions to the rotational constants, an assignment of the hot bands could be made on the basis of anharmonic corrections to the harmonic normal modes and by using the information contained in the Duschinsky matrix calculated by second order coupled cluster (CC2) theory. Fluorescence emission and (hot) absorption spectra of benzimidazole from Jalviste and Treshchalov [Chem. Phys. 1993, 172, 325] have been simulated using Franck-Condon integrals obtained from CC2 optimized geometries and Hessians.
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Affiliation(s)
- Christian Brand
- Institut für Physikalische Chemie I, Heinrich-Heine-Universität , D-40225 Düsseldorf, Germany
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Brand C, Oeltermann O, Wilke M, Schmitt M. Position matters: High resolution spectroscopy of 6-methoxyindole. J Chem Phys 2013; 138:024321. [DOI: 10.1063/1.4773468] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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14
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Huang WC, Lin YC, Tzeng WB. Mass-analyzed threshold ionization spectroscopy of 2,6-dimethylaniline, 2,6-dimethylaniline-NHD, and 2,6-dimethylaniline-ND2. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.09.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Yang SC, Tzeng WB. Mass-analyzed threshold ionization of deuterium substituted indazole and benzimidazole and site-specific H/D exchange reaction. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.10.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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16
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Müller CW, Newby JJ, Liu CP, Rodrigo CP, Zwier TS. Duschinsky mixing between four non-totally symmetric normal coordinates in the S1–S0 vibronic structure of (E)-phenylvinylacetylene: a quantitative analysis. Phys Chem Chem Phys 2010; 12:2331-43. [DOI: 10.1039/b919912h] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Kalkman I, Brand C, Vu TBC, Meerts WL, Svartsov YN, Dopfer O, Tong X, Müller-Dethlefs K, Grimme S, Schmitt M. The structure of phenol-Arn (n=1,2) clusters in their S0 and S1 states. J Chem Phys 2009; 130:224303. [DOI: 10.1063/1.3149780] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Vu TBC, Kalkman I, Meerts WL, Brand C, Svartsov YN, Wiedemann S, Weinkauf R, Schmitt M. The conformational landscape of 5-methoxytryptamine studied by rotationally resolved fluorescence spectroscopy and resonant ionization spectroscopy. Phys Chem Chem Phys 2009; 11:2433-40. [DOI: 10.1039/b819469f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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19
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Vu TBC, Kalkman I, Leo Meerts W, Svartsov YN, Jacoby C, Schmitt M. Rotationally resolved electronic spectroscopy of water clusters of 7-azaindole. J Chem Phys 2008; 128:214311. [DOI: 10.1063/1.2928637] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Brause R, Schmitt M, Kleinermanns K. Improved Determination of Structural Changes of 2-Pyridone-(H2O)1 upon Electronic Excitation. J Phys Chem A 2007; 111:3287-93. [PMID: 17419594 DOI: 10.1021/jp067572b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The change of the 2-pyridone-water cluster (2PYH(2)O) structure upon electronic excitation is determined by a Franck-Condon analysis of the intensities in the fluorescence emission spectra obtained via excitation of three different vibronic bands as well as a structural fit based on the rotational constants of eight isotopomers that have been reported by Held and Pratt (J. Am. Chem. Soc., 1993, 115, 9708]. A total of 93 emission band intensities were fit, together with the changes of rotational constants of 8 isotopomers. The geometry change upon electronic excitation to the pipi* state can be described by a strong and unsymmetrical elongation of the hydrogen bonds, a contraction of the OH bond involved in the cyclic cluster arrangement, and an unsymmetrical ring deformation. The resulting geometry changes are interpreted on the basis of ab initio calculations.
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Affiliation(s)
- Robert Brause
- Heinrich-Heine-Universität, Institut für Physikalische Chemie I, D-40225 Düsseldorf, Germany
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Chervenkov S, Wang P, Braun JE, Chakraborty T, Neusser HJ. Evidence for a C–H⋯π type weak interaction: 1 : 1 complex of styrene with acetylene studied by mass selective high-resolution UV spectroscopy and ab initio calculations. Phys Chem Chem Phys 2007; 9:837-45. [PMID: 17287877 DOI: 10.1039/b613085b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The 1 : 1 complex of styrene with acetylene has been studied by mass selective low- and high-resolution UV resonance-enhanced two-photon ionisation (R2PI) spectroscopy combined with genetic-algorithm-based computer-aided fit of the spectra with partial rotational resolution, and high level ab initio quantum chemistry calculations. Two stable conformeric geometries of the 1 : 1 complex of styrene and acetylene have been theoretically found: one with acetylene binding to styrene as a proton donor, and one with acetylene acting as a proton acceptor. From the analysis of the vibronic structure of the S1<-- S0 spectrum and the fit of the highly resolved spectrum of the 0 origin band of the complex it is shown that the favoured conformation is the one in which acetylene binds to the benzene ring of styrene through formation of a non-conventional hydrogen bond of C-H...pi type with no marked change of the transition moment orientation of styrene. The styrene moiety remains planar and the acetylene molecule is tilted by a small angle of 4 degrees relative to the C6 symmetry axis of the benzene ring, most likely due to the reduced symmetry of the benzene ring pi electrons rather than to a direct interaction with the vinyl group.
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Affiliation(s)
- Sotir Chervenkov
- Physikalische und Theoretische Chemie, Technische Universität München, Lichtenbergstr. 4, D-85748, Garching, Germany
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22
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Böhm M, Ratzer C, Schmitt M. The structure of p-chlorophenol and barrier to internal OH rotation in the S1-state. J Mol Struct 2006. [DOI: 10.1016/j.molstruc.2006.03.081] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Electronic excitation in the benzonitrile dimer: The intermolecular structure in the S0 and S1 state determined by rotationally resolved electronic spectroscopy. J Mol Struct 2006. [DOI: 10.1016/j.molstruc.2006.02.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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24
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Leo Meerts W, Schmitt M. Application of genetic algorithms in automated assignments of high-resolution spectra. INT REV PHYS CHEM 2006. [DOI: 10.1080/01442350600785490] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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25
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Schmitt M, Böhm M, Ratzer C, Krügler D, Kleinermanns K, Kalkman I, Berden G, Meerts WL. Determining the Intermolecular Structure in the S0 and S1 States of the Phenol Dimer by Rotationally Resolved Electronic Spectroscopy. Chemphyschem 2006; 7:1241-9. [PMID: 16680792 DOI: 10.1002/cphc.200500670] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The rotationally resolved UV spectra of the electronic origins of five isotopomers of the phenol dimer have been measured. The complex spectra are analyzed using a fitting strategy based on a genetic algorithm. The intermolecular geometry parameters have been determined from the inertial parameters for both electronic states and compared to the results of ab initio calculations. In the electronic ground state, a larger hydrogen-bond length than in the ab initio calculations is found together with a smaller tilt angle of the aromatic rings, which shows a more pronounced dispersion interaction. In the electronically excited state, the hydrogen-bond length decreases, as has been found for other hydrogen-bonded clusters of phenol, and the two aromatic rings are tilted less toward each other.
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Affiliation(s)
- Michael Schmitt
- Institut für Physikalische Chemie, Universitätsstrasse 26.43.02, 40225 Düsseldorf, Germany.
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