1
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Rinaman J, Murray C. Acetylacetone Photolysis at 280 nm Studied by Velocity-Map Ion Imaging. J Phys Chem A 2023; 127:6687-6696. [PMID: 37535453 PMCID: PMC10440790 DOI: 10.1021/acs.jpca.3c01653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 07/17/2023] [Indexed: 08/05/2023]
Abstract
The photolysis of acetylacetone (AcAc) has been studied using velocity-map ion imaging with pulsed nanosecond lasers. The enolone tautomer of AcAc (CH3C(O)CH═C(OH)CH3) was excited in the strong UV absorption band by UV pulses at 280 nm, preparing the S2(ππ*) state, and products were probed after a short time delay by single-photon VUV ionization at 118.2 nm. Two-color UV + VUV time-of-flight mass spectra show enhancement of fragments at m/z = 15, 42, 43, 58, and 85 at the lowest UV pulse energies and depletion of the parent ion at m/z = 100. Ion images of the five major fragments are all isotropic, indicating dissociation lifetimes that are long on the timescale of molecular rotation but shorter than the laser pulse duration (<6 ns). The m/z = 15 and 85 fragments have identical momentum distributions with moderate translational energy release, suggesting that they are formed as a neutral product pair and likely via a Norrish type I dissociation of the enolone to form CH3 + C(O)CH═C(OH)CH3 over a barrier on a triplet surface. The m/z = 43 fragment may be tentatively assigned to the alternative Norrish type I pathway that produces CH3CO + CH2C(O)CH3 on S0 following phototautomerization to the diketone, although alternative mechanisms involving dissociative ionization of a larger primary photoproduct cannot be conclusively ruled out. The m/z = 42 and 58 fragments are not momentum-matched and consequently are not formed as a neutral pair via a unimolecular dissociation pathway on S0. They also likely originate from the dissociative ionization of primary photofragments. RRKM calculations suggest that unimolecular dissociation pathways that lead to molecular products on S0 are generally slow, implying an upper-limit lifetime of <46 ns after excitation at 280 nm. Time-dependent measurements suggest that the observed photofragments likely do not arise from dissociative ionization of energized AcAc S0*.
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Affiliation(s)
- Johanna
E. Rinaman
- Department of Chemistry, University
of California, Irvine, Irvine, California 92697, United States
| | - Craig Murray
- Department of Chemistry, University
of California, Irvine, Irvine, California 92697, United States
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2
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Rousselot-Pailley P, Mascetti J, Pizzo A, Aupetit C, Sobanska S, Coussan S. UV photoreaction pathways of acetylacetaldehyde trapped in cryogenic matrices. J Chem Phys 2023; 158:084302. [PMID: 36859085 DOI: 10.1063/5.0133636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The broadband UV photochemistry kinetics of acetylacetaldehyde, the hybrid form between malonaldehyde and acetylacetone (the two other most simple molecules exhibiting an intramolecular proton transfer), trapped in four cryogenic matrices, neon, nitrogen, argon, and xenon, has been followed by FTIR and UV spectroscopy. After deposition, only the two chelated forms are observed while they isomerize upon UV irradiation toward nonchelated species. From previous UV irradiation effects, we have already identified several nonchelated isomers, capable, in turn, of isomerizing and fragmenting; even fragmentation seems to be most unlikely due to cryogenic cages confinement. Based on these findings, we have attempted an approach to understand the reaction path of electronic relaxation. Indeed, we have demonstrated, in previous studies, that in the case of malonaldehyde, this electronic relaxation pathway proceeds through singlet states while it proceeds through triplet ones in the case of acetylacetone. We observed CO and CO2 formations when photochemistry is almost observed among nonchelated forms, i.e., when the parent molecule is almost totally consumed. In order to identify a triplet state transition, we have tried to observe a "heavy atom effect" by increasing the weight of the matrix gas, from Ne to Xe, and to quench the T1 state by doping the matrices with O2. It appears that, as in the case of acetylacetone, it is the nonchelated forms that fragment. It also appears that these fragmentations certainly take place in the T1 triplet state and originate in an Π* ← n transition.
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Affiliation(s)
- P Rousselot-Pailley
- Aix-Marseille Univ., Centrale Marseille, CNRS, iSm2 UMR 7313, Marseille, France
| | - J Mascetti
- Institut des Sciences Moléculaires, Université de Bordeaux 1, CNRS UMR 5255, Talence, France
| | - A Pizzo
- Aix-Marseille Univ., CNRS, PIIM, Marseille, France
| | - C Aupetit
- Institut des Sciences Moléculaires, Université de Bordeaux 1, CNRS UMR 5255, Talence, France
| | - S Sobanska
- Institut des Sciences Moléculaires, Université de Bordeaux 1, CNRS UMR 5255, Talence, France
| | - S Coussan
- Aix-Marseille Univ., CNRS, PIIM, Marseille, France
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3
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Uchkina D, Vlasov S, Ponomarev A. Effect of boiling on the radiolysis of acetylacetone. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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4
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Yan H, Luo M, Chen Q, Jeong T, Zhang J, Wang L. Efficacy and mechanism of chemical-free VUV/UV process for oxytetracycline degradation: Continuous-flow experiment and CFD modeling. CHEMICAL ENGINEERING JOURNAL ADVANCES 2020. [DOI: 10.1016/j.ceja.2020.100059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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5
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Rousselot-Pailley P, Sobanska S, Ferré N, Coussan S. UV Photochemistry of Acetylacetaldehyde Trapped in Cryogenic Matrices. J Phys Chem A 2020; 124:4916-4928. [PMID: 32441945 DOI: 10.1021/acs.jpca.0c02512] [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 broad band UV photochemistry of acetylacetaldehyde, the hybrid form between malonaldehyde and acetylacetone (the two other most simple molecules exhibiting an intramolecular proton transfer), trapped in four cryogenic matrices, neon, nitrogen, argon, and xenon, has been studied by IRTF spectroscopy. These experimental results have been supported by B3LYP/6-311G++(2d,2p) calculations in order to get S0 minima together with their harmonic frequencies. On those minima, we have also calculated their vibrationally resolved UV absorption spectra at the time-dependent DFT ωB97XD/6-311++G(2d,2p) level. After deposition, only the two chelated forms are observed while they isomerize upon UV irradiation toward nonchelated species. From UV irradiation effects we have identified several nonchelated isomers, capable, in turn, of isomerizing and fragmenting, even if this last phenomenon seems to be most unlikely due to cryogenic cages confinement. On the basis of these findings, we have attempted a first approach to the reaction path of electronic relaxation. It appeared that, as with acetylacetone, the path of electronic relaxation seems to involve triplet states.
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Affiliation(s)
- P Rousselot-Pailley
- Centrale Marseille, CNRS, iSm2 UMR 7313, Aix-Marseille Université, Marseille, France
| | - S Sobanska
- Institut des Sciences Moléculaires, Université de Bordeaux 1, CNRS UMR 5255, Talence, France
| | - N Ferré
- CNRS, ICR, Aix-Marseille Université,, Marseille, France
| | - S Coussan
- CNRS, PIIM, Aix-Marseille Université, Marseille, France
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6
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Kotsina N, Candelaresi M, Saalbach L, Zawadzki MM, Crane SW, Sparling C, Townsend D. Short-wavelength probes in time-resolved photoelectron spectroscopy: an extended view of the excited state dynamics in acetylacetone. Phys Chem Chem Phys 2020; 22:4647-4658. [DOI: 10.1039/d0cp00068j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved photoelectron spectroscopy using a vacuum ultraviolet probe brings new insight to the excited state dynamics operating in acetylacetone.
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Affiliation(s)
- Nikoleta Kotsina
- Institute of Photonics & Quantum Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - Marco Candelaresi
- Institute of Photonics & Quantum Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - Lisa Saalbach
- Institute of Photonics & Quantum Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | | | - Stuart W. Crane
- Institute of Photonics & Quantum Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - Chris Sparling
- Institute of Photonics & Quantum Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - Dave Townsend
- Institute of Photonics & Quantum Sciences
- Heriot-Watt University
- Edinburgh
- UK
- Institute of Chemical Sciences
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7
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Antonov I, Voronova K, Chen MW, Sztáray B, Hemberger P, Bodi A, Osborn DL, Sheps L. To Boldly Look Where No One Has Looked Before: Identifying the Primary Photoproducts of Acetylacetone. J Phys Chem A 2019; 123:5472-5490. [DOI: 10.1021/acs.jpca.9b04640] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Ivan Antonov
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Krisztina Voronova
- Department of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Ming-Wei Chen
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Bálint Sztáray
- Department of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | | | - Andras Bodi
- Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - David L. Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
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8
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Bhattacherjee A, Pemmaraju CD, Schnorr K, Attar AR, Leone SR. Ultrafast Intersystem Crossing in Acetylacetone via Femtosecond X-ray Transient Absorption at the Carbon K-Edge. J Am Chem Soc 2017; 139:16576-16583. [DOI: 10.1021/jacs.7b07532] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Aditi Bhattacherjee
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Chaitanya Das Pemmaraju
- Theory
Institute for Materials and Energy Spectroscopies, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Kirsten Schnorr
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrew R. Attar
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Stephen R. Leone
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Physics, University of California, Berkeley, California 94720, United States
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9
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Srinivas D, Sajeev Y, Upadhyaya HP. Resonance enhanced multiphoton ionization − time of flight (REMPI-TOF) detection of Br ( 2 P j ) atoms in the photodissociation of 4-bromo-2,3,5,6-tetrafluoropyridine at 234 nm: Effect of low-lying πσ* states. J Photochem Photobiol A Chem 2017. [DOI: 10.1016/j.jphotochem.2017.05.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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10
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De Vries B, Muyskens M. Fluorine atom influence on intramolecular hydrogen bonding, isomerization and methyl group rotation in fluorinated acetylacetones. COMPUT THEOR CHEM 2016. [DOI: 10.1016/j.comptc.2016.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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11
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Liu Y, He X, Fu Y, Dionysiou DD. Kinetics and mechanism investigation on the destruction of oxytetracycline by UV-254nm activation of persulfate. JOURNAL OF HAZARDOUS MATERIALS 2016; 305:229-239. [PMID: 26686482 DOI: 10.1016/j.jhazmat.2015.11.043] [Citation(s) in RCA: 163] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 10/19/2015] [Accepted: 11/21/2015] [Indexed: 06/05/2023]
Abstract
Oxytetracycline (OTC), an important broad-spectrum antibiotic, has been detected extensively in various environmental systems, which may have a detrimental impact on ecosystem and human health through the development of drug resistant bacteria and pathogens. In this study, the degradation of OTC was evaluated by UV-254nm activated persulfate (PS). The observed UV fluence based pseudo first-order rate constant (kobs) was found to be the highest at near neutral pH conditions (pH 5.5-8.5). Presence of various natural water constituents had different effects on OTC degradation, with a significant enhancement in the presence of bicarbonate or Cu(2+). Limited elimination of total organic carbon (TOC) and PS was observed during the mineralization of OTC. Transformation byproducts in the presence and absence of hydroxyl radical scavenging agent tert-butanol (t-BuOH) were identified using ultra-high definition accurate-mass quadrupole time-of-flight liquid chromatography/mass spectrometer (LC-QTOF/MS). Potential OTC degradation mechanism was subsequently proposed revealing four different reaction pathways by SO4(-) reaction including hydroxylation (+16Da), demethylation (-14Da), decarbonylation (-28Da) and dehydration (-18Da). This study suggests that UV-254nm/PS is a promising treatment technology for the control of water pollution caused by emerging contaminants such as OTC.
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Affiliation(s)
- Yiqing Liu
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756, China; Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012, United States
| | - Xuexiang He
- Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012, United States
| | - Yongsheng Fu
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756, China
| | - Dionysios D Dionysiou
- Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012, United States.
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12
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Upadhyaya HP. Dynamics of OH formation in the photodissociation of enolic-acetonylacetone at 193nm. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2015.11.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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13
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Gutiérrez-Quintanilla A, Chevalier M, Crépin C. Double deuterated acetylacetone in neon matrices: infrared spectroscopy, photoreactivity and the tunneling process. Phys Chem Chem Phys 2016; 18:20713-25. [DOI: 10.1039/c6cp02796b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Open enol conformers of double deuterated acetylacetone are produced by UV and IR irradiation, allowing the analysis of the tunnelling effect between them.
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Affiliation(s)
| | - Michèle Chevalier
- Institut des Sciences Moléculaires d'Orsay (ISMO)
- Bât.210
- UMR 8214
- CNRS
- Univ. Paris-Sud 11
| | - Claudine Crépin
- Institut des Sciences Moléculaires d'Orsay (ISMO)
- Bât.210
- UMR 8214
- CNRS
- Univ. Paris-Sud 11
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14
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Khemiri N, Messaoudi S, Abderrabba M, Spighi G, Gaveau MA, Briant M, Soep B, Mestdagh JM, Hochlaf M, Poisson L. Photoionization of Benzophenone in the Gas Phase: Theory and Experiment. J Phys Chem A 2015; 119:6148-54. [PMID: 25866992 DOI: 10.1021/acs.jpca.5b02706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report on the single photoionization of jet-cooled benzophenone using a tunable source of VUV synchrotron radiation coupled with a photoion/photoelectron coincidence acquisition device. The assignment and the interpretation of the spectra are based on a characterization by ab initio and density functional theory calculations of the geometry and of the electronic states of the cation. The absence of structures in the slow photoelectron spectrum is explained by a congestion of the spectrum due to the dense vibrational progressions of the very low frequency torsional mode in the cation either in pure form or in combination bands. Also a high density of electronic states has been found in the cation. Presently, we estimate the experimental adiabatic and vertical ionization energy of benzophenone at 8.80 ± 0.01 and 8.878 ± 0.005 eV, respectively. The ionization energy as well as the energies of the excited states are compared to the calculated ones.
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Affiliation(s)
- Noura Khemiri
- †Laboratoire Matériaux, Molécules et Applications, Institut Préparatoire aux Etudes Scientifiques et Techniques, La Marsa, Université de Carthage, Carthage, Tunisie
| | - Sabri Messaoudi
- †Laboratoire Matériaux, Molécules et Applications, Institut Préparatoire aux Etudes Scientifiques et Techniques, La Marsa, Université de Carthage, Carthage, Tunisie
| | - Manef Abderrabba
- †Laboratoire Matériaux, Molécules et Applications, Institut Préparatoire aux Etudes Scientifiques et Techniques, La Marsa, Université de Carthage, Carthage, Tunisie
| | - Gloria Spighi
- ‡CEA, CNRS, IRAMIS/LIDyL/Laboratoire Francis Perrin URA2453, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Marc-André Gaveau
- ‡CEA, CNRS, IRAMIS/LIDyL/Laboratoire Francis Perrin URA2453, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Marc Briant
- ‡CEA, CNRS, IRAMIS/LIDyL/Laboratoire Francis Perrin URA2453, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Benoît Soep
- §CNRS, CEA, IRAMIS/LIDyL/Laboratoire Francis Perrin URA2453, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Jean-Michel Mestdagh
- §CNRS, CEA, IRAMIS/LIDyL/Laboratoire Francis Perrin URA2453, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Majdi Hochlaf
- ∥Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée, France
| | - Lionel Poisson
- §CNRS, CEA, IRAMIS/LIDyL/Laboratoire Francis Perrin URA2453, CEA Saclay, 91191 Gif-sur-Yvette, France
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15
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Antonov IO, Kwok J, Zádor J, Sheps L. A Combined Experimental and Theoretical Study of the Reaction OH + 2-Butene in the 400–800 K Temperature Range. J Phys Chem A 2015; 119:7742-52. [DOI: 10.1021/acs.jpca.5b01012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ivan O. Antonov
- Combustion
Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Justin Kwok
- Combustion
Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Judit Zádor
- Combustion
Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Leonid Sheps
- Combustion
Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
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16
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Verma PK, Steinbacher A, Koch F, Nuernberger P, Brixner T. Monitoring ultrafast intramolecular proton transfer processes in an unsymmetric β-diketone. Phys Chem Chem Phys 2015; 17:8459-66. [DOI: 10.1039/c4cp05811a] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Electronic excitation of a UV-absorbing unsymmetric β-diketone discloses intramolecular proton transfer among electronic ground as well as excited states.
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Affiliation(s)
- Pramod Kumar Verma
- Institut für Physikalische und Theoretische Chemie
- Universität Würzburg
- Am Hubland
- Germany
| | - Andreas Steinbacher
- Institut für Physikalische und Theoretische Chemie
- Universität Würzburg
- Am Hubland
- Germany
| | - Federico Koch
- Institut für Physikalische und Theoretische Chemie
- Universität Würzburg
- Am Hubland
- Germany
| | - Patrick Nuernberger
- Institut für Physikalische und Theoretische Chemie
- Universität Würzburg
- Am Hubland
- Germany
- Physikalische Chemie II
| | - Tobias Brixner
- Institut für Physikalische und Theoretische Chemie
- Universität Würzburg
- Am Hubland
- Germany
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17
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Verma PK, Koch F, Steinbacher A, Nuernberger P, Brixner T. Ultrafast UV-Induced Photoisomerization of Intramolecularly H-Bonded Symmetric β-Diketones. J Am Chem Soc 2014; 136:14981-9. [DOI: 10.1021/ja508059p] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Pramod Kumar Verma
- Institut für Physikalische
und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Federico Koch
- Institut für Physikalische
und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Andreas Steinbacher
- Institut für Physikalische
und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Patrick Nuernberger
- Institut für Physikalische
und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Tobias Brixner
- Institut für Physikalische
und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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18
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SenGupta S, Upadhyaya HP, Kumar A, Naik PD. OH formation dynamics in 193nm photolysis of 2-methoxyethanol: A laser induced fluorescence study. Chem Phys 2014. [DOI: 10.1016/j.chemphys.2014.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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19
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Ómarsson B, Engmann S, Ingólfsson O. Dissociative electron attachment to the complexation ligands hexafluoroacetylacetone, trifluoroacetylacetone and acetylacetone; a comparative experimental and theoretical study. RSC Adv 2014. [DOI: 10.1039/c4ra04451g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Influence of fluorination on the negative ion resonances and dissociation dynamics in electron attachment to acetylacetone, trifluoroacetylacetone and hexafluoroacetylacetone are explored through calculations and experiments.
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20
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Wang M, Liu X, Pan B, Zhang S. Photodegradation of Acid Orange 7 in a UV/acetylacetone process. CHEMOSPHERE 2013; 93:2877-2882. [PMID: 24079997 DOI: 10.1016/j.chemosphere.2013.08.082] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 06/02/2023]
Abstract
Acetylacetone (AcAc) was employed as a photo-activator for the degradation of Acid Orange 7 (AO7) under UV irradiation. The feasibility of this process (named as UV/AcAc) was evaluated through comparison with the well-established UV/H2O2 process in terms of absorption spectrum and the biodegradability of the solutions. A complete decoloration of the AO7 solution could be fulfilled with AcAc at mM level. A self-acceleration phenomenon was observed for the UV/AcAc process. The pseudo first-order decoloration rate constant of AO7 in the UV/AcAc process was several times higher than that in the UV/H2O2 process, depending on the irradiation conditions. The BOD to COD ratio of the solutions increased from below 0.1 to above 0.3, along with a slight mineralization. Based on degradation product analysis, the possible pathways for AO7 degradation in the UV/AcAc process were proposed.
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Affiliation(s)
- Mengshu Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
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21
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Kawade M, Saha A, Upadhyaya HP, Kumar A, Naik PD. Photodissociation dynamics of enolic 1,2-cyclohexanedione at 266, 248, and 193 nm: mechanism and nascent state product distribution of OH. J Phys Chem A 2013; 117:2415-26. [PMID: 23444923 DOI: 10.1021/jp311251m] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photodissociation dynamics of 1,2-cyclohexanedione (CHD), which exists in enolic form in gas phase, is studied using pulsed laser photolysis (LP)-laser induced fluorescence (LIF) "pump-and-probe" technique at room temperature. The nascent state distribution of the OH radical, formed after initial photoexcitation of the molecule to it is (π, π*) and Rydberg states, is determined. The initial (π, π*) and Rydberg states are prepared by excitation with the fourth harmonic output of Nd:YAG (266 nm)/KrF (248 nm) and ArF (193 nm) lasers, respectively. The ro-vibrational distribution of the nascent OH photofragment is measured in collision-free conditions using LIF. The OH fragments are formed in the vibrationally cold state at all the above wavelengths of excitation but differ in rotational state distributions. At 266 nm photolysis, the rotational population of OH shows a curvature in Boltzmann plot, which is fairly described by two types of Boltzmann-like distributions characterized by rotational temperatures of 3100 ± 100 and 900 ± 80 K. However, at 248 nm photolysis, the rotational distribution is described by a single rotational temperature of 950 ± 80 K. The spin-orbit and Λ-doublets ratios of OH fragments formed in the dissociation process are also measured. The average translational energy in the center-of-mass coordinate, partitioned into the photofragment pairs of the OH formation channels, is determined to be 12.5 ± 3.0, 12.7 ± 3.0, and 12.0 ± 3.0 kcal/mol at 266, 248, and 193 nm excitation, respectively. The energy partitioning into various degrees of freedom of products is interpreted with the help of different models, namely, statistical, impulsive, and hybrid models. To understand the nature of the dissociative potential energy surface involved in the OH formation channel, detailed ab initio calculations are performed using configuration interaction-singles (CIS) method. It is proposed that at 266 nm photolysis, the OH fragment is formed from two different excited state structures, one with a strong H bonding, similar to that in the ground state, and another without effective H bonding, whereas, at 248 nm photodissociation, it seems that the OH formation occurs mainly from the excited state, which lacks effective H-bonding. At 193 nm excitation, the initially prepared population in the Rydberg state crosses over to a nearby σ* repulsive state along the C-O bond, from where the dissociation takes place. The exit barrier for the OH dissociation channel is estimated to be 14 kcal/mol. The existence of dynamical constraint due to strong hydrogen bond in the ground state is effectively present in the dissociation process at 266 and somewhat deficient at 248 nm photolysis.
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Affiliation(s)
- Monali Kawade
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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Penzkofer A. Phosphorescence quantum yield determination with time-gated fluorimeter and Tb(III)-acetylacetonate as luminescence reference. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2013.01.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lozada-García RR, Ceponkus J, Chevalier M, Chin W, Mestdagh JM, Crépin C. Photochemistry of acetylacetone isolated in parahydrogen matrices upon 266 nm irradiation. Phys Chem Chem Phys 2012; 14:3450-9. [DOI: 10.1039/c2cp23913b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Trivella A, Wassermann TN, Mestdagh JM, Manca Tanner C, Marinelli F, Roubin P, Coussan S. New insights into the photodynamics of acetylacetone: isomerization and fragmentation in low-temperature matrixes. Phys Chem Chem Phys 2010; 12:8300-10. [DOI: 10.1039/c003593a] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- A Trivella
- Laboratoire Physique des Interactions Ioniques et Moléculaires, UMR 6633, Université de Provence-CNRS, Centre St-Jérôme, 13397 Marseille Cedex 20, France
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Cheng SB, Zhou CH, Yin HM, Sun JL, Han KL. OH produced from o-nitrophenol photolysis: A combined experimental and theoretical investigation. J Chem Phys 2009; 130:234311. [DOI: 10.1063/1.3152635] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Cheng SB, Zhou CH, Yin HM, Sun JL, Han KL. Photolysis ofo-Nitrobenzaldehyde in the Gas Phase: A New OH.Formation Channel. Chemphyschem 2009; 10:1135-42. [DOI: 10.1002/cphc.200800735] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Yue XF, Sun JL, Yin HM, Wei Q, Han KL. Photodissociation Dynamics of Alkyl Nitrites at 266 and 355 nm: The OH Product Channel. J Phys Chem A 2009; 113:3303-10. [DOI: 10.1021/jp810731d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xian-Fang Yue
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Ju-Long Sun
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Hong-Ming Yin
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Qiang Wei
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Ke-Li Han
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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Rusteika N, Brogaard RY, Sølling TI, Rudakov FM, Weber PM. Excited-State Ions in Femtosecond Time-Resolved Mass Spectrometry: An Investigation of Highly Excited Chloroamines. J Phys Chem A 2008; 113:40-3. [DOI: 10.1021/jp807227e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Nerijus Rusteika
- University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, and Department of Chemistry, Brown University, Providence, Rhode Island 02912
| | - Rasmus Y. Brogaard
- University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, and Department of Chemistry, Brown University, Providence, Rhode Island 02912
| | - Theis I. Sølling
- University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, and Department of Chemistry, Brown University, Providence, Rhode Island 02912
| | - Fedor M. Rudakov
- University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, and Department of Chemistry, Brown University, Providence, Rhode Island 02912
| | - Peter M. Weber
- University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, and Department of Chemistry, Brown University, Providence, Rhode Island 02912
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Zhou S, Barnes I, Zhu T, Bejan I, Albu M, Benter T. Atmospheric chemistry of acetylacetone. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:7905-7910. [PMID: 19031879 DOI: 10.1021/es8010282] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A kinetic study on the reactions of the OH radical and ozone with acetylacetone (AcAc) has been performed in a 1080 L quartz glass reaction chamber using in situ FTIR spectroscopy analysis. Temperature dependent rate coefficients for the reaction of AcAc with the OH radical were determined over the temperature range 285-310 K using the relative kinetic method. The following Arrhenius expression was derived: k = 3.35 x 10(-12) exp((983 +/- 130)/T) cm3 molecule(-1) s(-1), where the indicated error is the two least-squares deviation. A rate coefficient (in units of cm3 molecule(-1) s(-1)) of (1.03 +/- 0.31) x 10(-18) has been obtained at (298 +/- 3) K for the reaction of ozone with AcAc. A product investigation on the gas-phase reaction of OH radical with AcAc was conducted in a 405 L borosilicate glass chamber using in situ FTIR spectroscopy to monitor reactants and products. Methylglyoxal, acetic acid, peroxy acetic nitrate (PAN) were positively identified as products with molar yields of (20.8 +/- 4.5)%, (16.9 +/- 3.4)%, and (2.0 +/- 0.5)%, respectively. From the residual infrared spectrum the main products are attributed to 2,3,4-pentantrione (CH3-CO-CO-CO-CH3) and its hydrated analogue pentan-2,3-dione-4-diol (CH3-CO-CO-C(OH)2-CH3). Based on the observed products, a simplified mechanism for the reaction of the OH radical with AcAc is proposed.
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Affiliation(s)
- Shouming Zhou
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Science, Peking University, 100871 Beijing, China
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Poisson L, Roubin P, Coussan S, Soep B, Mestdagh JM. Ultrafast Dynamics of Acetylacetone (2,4-Pentanedione) in the S2 State. J Am Chem Soc 2008; 130:2974-83. [DOI: 10.1021/ja0730819] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Lionel Poisson
- Laboratoire Francis Perrin (CNRS-URA-2453), DSM/IRAMIS/Service des Photons, Atomes et Molécules, C.E.A. Saclay, F-91191 Gif-sur-Yvette cedex, France, and Laboratoire de Physique des Interactions Ioniques et Moléculaires, CNRS-UMR-6633, Université de Provence, Centre St-Jérôme, F-13397 Marseille cedex 20, France
| | - Pascale Roubin
- Laboratoire Francis Perrin (CNRS-URA-2453), DSM/IRAMIS/Service des Photons, Atomes et Molécules, C.E.A. Saclay, F-91191 Gif-sur-Yvette cedex, France, and Laboratoire de Physique des Interactions Ioniques et Moléculaires, CNRS-UMR-6633, Université de Provence, Centre St-Jérôme, F-13397 Marseille cedex 20, France
| | - Stéphane Coussan
- Laboratoire Francis Perrin (CNRS-URA-2453), DSM/IRAMIS/Service des Photons, Atomes et Molécules, C.E.A. Saclay, F-91191 Gif-sur-Yvette cedex, France, and Laboratoire de Physique des Interactions Ioniques et Moléculaires, CNRS-UMR-6633, Université de Provence, Centre St-Jérôme, F-13397 Marseille cedex 20, France
| | - Benoît Soep
- Laboratoire Francis Perrin (CNRS-URA-2453), DSM/IRAMIS/Service des Photons, Atomes et Molécules, C.E.A. Saclay, F-91191 Gif-sur-Yvette cedex, France, and Laboratoire de Physique des Interactions Ioniques et Moléculaires, CNRS-UMR-6633, Université de Provence, Centre St-Jérôme, F-13397 Marseille cedex 20, France
| | - Jean-Michel Mestdagh
- Laboratoire Francis Perrin (CNRS-URA-2453), DSM/IRAMIS/Service des Photons, Atomes et Molécules, C.E.A. Saclay, F-91191 Gif-sur-Yvette cedex, France, and Laboratoire de Physique des Interactions Ioniques et Moléculaires, CNRS-UMR-6633, Université de Provence, Centre St-Jérôme, F-13397 Marseille cedex 20, France
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Pola J, Ouchi A, Bakardjieva S, Urbanová M, Boháček J, Šubrt J. Laser photolytic approach to Cu/polymer sols and Cu/polymer nanocomposites with amorphous Cu phase. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2007.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Mohacek-Grosev V, Furić K, Ivanković H. Luminescence and Raman Spectra of Acetylacetone at Low Temperatures. J Phys Chem A 2007; 111:5820-7. [PMID: 17566988 DOI: 10.1021/jp067157j] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Raman spectra of acetylacetone were recorded for molecules isolated in an argon matrix at 10 K and for a polycrystalline sample. In the solid sample, broad bands appear superimposed on a much weaker Raman spectrum corresponding mainly to the stable enol form. The position of these bands depends on the excitation wavelength (514.5 and 488.8 nm argon ion laser lines were used), sample temperature, and cooling history. They are attributed to transitions from an excited electronic state to various isomer states in the ground electronic state. Laser photons have energies comparable to energies of a number of excited triplet states predicted for a free acetylacetone molecule (Chen, X.-B.; Fang, W.-H.; Phillips, D. L. J. Phys. Chem. A 2006, 110, 4434). Since singlet-to-triplet photon absorption transitions are forbidden, states existing in the solid have mixed singlet/triplet character. Their decay results in population of different isomer states, which except for the lowest isomers SYN enol, TS2 enol (described in Matanović I.; Doslić, N. J. Phys. Chem. A 2005, 109, 4185), and the keto form, which can be detected in the Raman spectra of the solid, are not vibrationally resolved. Differential scanning calorimetry detected two signals upon cooling of acetylacetone, one at 229 K and one at 217 K, while upon heating, they appear at 254 and 225 K. The phase change at higher temperature is attributed to a freezing/melting transition, while the one at lower temperature seems to correspond to freezing/melting of keto domains, as suggested by Johnson et al. (Johnson, M. R.; Jones, N. H.; Geis, A; Horsewill. A. J.; Trommsdorff, H. P. J. Chem. Phys. 2002, 116, 5694). Using matrix isolation in argon, the vibrational spectrum of acetylacetone at 10 K was recorded. Strong bands at 1602 and 1629 cm(-1) are assigned as the SYN enol bands, while a weaker underlying band at 1687 cm(-1) and a medium shoulder at 1617 cm(-1) are assigned as TS2 enol bands.
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Affiliation(s)
- Vlasta Mohacek-Grosev
- Ruder Bosković Institute, P.O. Box 180, Bijenicka c. 54, 10002 Zagreb, Croatia, and Faculty of Chemical Engineering and Technology, Marulićev trg 19, 10000 Zagreb, Croatia.
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Trivella A, Roubin P, Theulé P, Rajzmann M, Coussan S, Manca C. UV and IR Photoisomerization of Acetylacetone Trapped in a Nitrogen Matrix. J Phys Chem A 2007; 111:3074-81. [PMID: 17394292 DOI: 10.1021/jp068763h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
UV- and IR-induced photoisomerization of acetylacetone trapped in a nitrogen matrix at 4.3 K have been carried out using a tunable optical parametric oscillator type laser, or a mercury vapor lamp, coupled with Fourier Transform IR and UV spectroscopies. After deposition, the main form present in the cryogenic matrix is that chelated (enol). Upon UV irradiation, the intramolecular H bond is broken leading to nonchelated isomers among seven possible open forms. These forms have then been irradiated by resonant pi* <-- pi UV irradiation, or by resonant nuOH irradiation. The selective UV irradiation allows us to suggest a first vibrational assignment while the nuOH irradiation leads us to observe interconversions between the nonchelated isomers. In order to support our vibrational assignment, we have carried out theoretical calculations at the B3LYP/6-311++G(2d,2p) level of theory. This study shows that only five isomers are observed among eight postulated.
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Affiliation(s)
- A Trivella
- Laboratoire Physique des Interactions Ioniques et Moléculaires, UMR 6633, Université de Provence-CNRS, Centre St-Jérôme, 13397 Marseille Cedex 20, France
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Chen XB, Fang WH, Phillips DL. Theoretical Studies of the Photochemical Dynamics of Acetylacetone: Isomerzation, Dissociation, and Dehydration Reactions. J Phys Chem A 2006; 110:4434-41. [PMID: 16571047 DOI: 10.1021/jp057306i] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The potential energy surfaces of the C-O cleavage, rotational isomerization, keto-enolic tautomerization, and dehydration reactions of acetylacetone in the lowest triplet and ground states have been determined using the complete active space self-consistent field and density functional theory methods. The main photochemical mechanism obtained indicates that the acetylacetone molecule in the S(2)((1)pipi*) state can relax to the T(1)((3)pipi*) state via the S(2)-S(1) vibronic interaction and an S(1)/T(1)/T(2) intersection. The C-O fission pathway is the predominant dissociation process in the T(1)((3)pipi) state. Rotational isomerization reactions proceed difficultly in the ground state but very easily in the T(1)((3)pipi*) state. Keto-enolic tautomerization takes place with little probability for acetylacetone in the gas phase.
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Affiliation(s)
- Xue-Bo Chen
- Department of Chemistry, Beijing Normal University, Beijing 100875, China
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Coussan S, Ferro Y, Trivella A, Rajzmann M, Roubin P, Wieczorek R, Manca C, Piecuch P, Kowalski K, Włoch M, Kucharski SA, Musiał M. Experimental and Theoretical UV Characterizations of Acetylacetone and Its Isomers. J Phys Chem A 2006; 110:3920-6. [PMID: 16539413 DOI: 10.1021/jp056834r] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cryogenic matrix isolation experiments have allowed the measurement of the UV absorption spectra of the high-energy non-chelated isomers of acetylacetone, these isomers being produced by UV irradiation of the stable chelated form. Their identification has been done by coupling selective UV-induced isomerization, infrared spectroscopy, and harmonic vibrational frequency calculations using density functional theory. The relative energies of the chelated and non-chelated forms of acetylacetone in the S0 state have been obtained using density functional theory and coupled-cluster methods. For each isomer of acetylacetone, we have calculated the UV transition energies and dipole oscillator strengths using the excited-state coupled-cluster methods, including EOMCCSD (equation-of-motion coupled-cluster method with singles and doubles) and CR-EOMCCSD(T) (the completely renormalized EOMCC approach with singles, doubles, and non-iterative triples). For dipole-allowed transition energies, there is a very good agreement between experiment and theory. In particular, the CR-EOMCCSD(T) approach explains the blue shift in the electronic spectrum due to the formation of the non-chelated species after the UV irradiation of the chelated form of acetylacetone. Both experiment and CR-EOMCCSD(T) theory identify two among the seven non-chelated forms to be characterized by red-shifted UV transitions relative to the remaining five non-chelated isomers.
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Affiliation(s)
- S Coussan
- Laboratoire Physique des Interactions Ioniques et Moléculaires, UMR 6633, Université de Provence-CNRS, Centre St-Jérôme, 13397 Marseille Cedex 20, France.
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Rate coefficients for the reactions of OH radicals with the keto/enol tautomers of 2,4-pentanedione and 3-methyl-2,4-pentanedione, allyl alcohol and methyl vinyl ketone using the enols and methyl nitrite as photolytic sources of OH. J Photochem Photobiol A Chem 2005. [DOI: 10.1016/j.jphotochem.2005.08.031] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Dhanya S, Upadhyaya HP, Kumar A, Naik PD, Saini RD. Photodissociation dynamics of acetoxime in gas phase. J Chem Phys 2005; 122:184322. [PMID: 15918719 DOI: 10.1063/1.1897369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dynamics of photodissociation of acetoxime at 193 nm, leading to the formation of (CH3)2C=N and OH fragments, has been investigated. The nascent OH radicals, which are both rotationally and vibrationally excited, were probed by laser photolysis-laser induced fluorescence technique. OH fragments in both v" = 1 and v" = 0 vibrational states were detected with a ratio of population in the higher to lower level of 0.07+/-0.01. The rotational temperatures of v" = 0 and 1 levels of OH radicals are 2650+/-150 K and 1290+/-20 K, respectively. More than 30% of the available energy, i.e., 115+/-21 kJ mol(-1) is partitioned into the relative translational energy of the fragments. The results of excited electronic state and transition state calculations at the configuration interaction with single electronic excitation level suggest that the dissociation takes place with an exit barrier of approximately 126 kJ mol(-1) at the triplet state (T2) potential energy surface, formed by internal conversions/intersystem crossing from the initially populated S2 state. Using the calculated transition state geometry and its energy, the observed energy distribution pattern can be reproduced by the hybrid model within experimental uncertainties. The presence of an exit barrier is further supported by the observation of N-OH dissociation upon 248 nm excitation, where the relative translational energy of the fragments is found to be approximately 96 kJ mol(-1). The photodissociation dynamics of acetoxime is compared with C-OH dissociation in enols and carboxylic acid and N-OH dissociation in nitrous acid. The observed emission (lambda(max)=430 nm) and the N-OH dissociation dynamics indicate crossing of the initially populated state to an emissive state of acetoxime, which is different from the dissociative state.
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Affiliation(s)
- Suresh Dhanya
- Radiation Chemistry & Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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Xu S, Park ST, Feenstra JS, Srinivasan R, Zewail AH. Ultrafast Electron Diffraction: Structural Dynamics of the Elimination Reaction of Acetylacetone. J Phys Chem A 2004. [DOI: 10.1021/jp0403689] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Shoujun Xu
- Laboratory for Molecular Sciences, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
| | - Sang Tae Park
- Laboratory for Molecular Sciences, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
| | - Jonathan S. Feenstra
- Laboratory for Molecular Sciences, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
| | - Ramesh Srinivasan
- Laboratory for Molecular Sciences, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
| | - Ahmed H. Zewail
- Laboratory for Molecular Sciences, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
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