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Hickson KM, Loison JC. Kinetic Study of the Gas-Phase O( 1D) + CH 3OH and O( 1D) + CH 3CN Reactions: Low-Temperature Rate Constants and Atomic Hydrogen Product Yields. J Phys Chem A 2022; 126:3903-3913. [PMID: 35687018 DOI: 10.1021/acs.jpca.2c01946] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Atomic oxygen in its first excited singlet state, O(1D), is an important species in the photochemistry of several planetary atmospheres and has been predicted to be a potentially important reactive species on interstellar ices. Here, we report the results of a kinetic study of the reactions of O(1D) with methanol, CH3OH, and acetonitrile, CH3CN, over the 50-296 K temperature range. A continuous supersonic flow reactor is used to attain these low temperatures coupled with pulsed laser photolysis and pulsed laser-induced fluorescence to generate and monitor O(1D) atoms, respectively. Secondary experiments examining the atomic hydrogen product channels of these reactions are also performed, through laser-induced fluorescence measurements of H(2S) atom formation. On the kinetic side, the rate constants for these reactions are seen to be large (>2 × 10-10 cm3 s-1) and consistent with barrierless reactions, although they display contrasting dependences as a function of temperature. On the product formation side, both reactions are seen to yield non-negligible quantities of atomic hydrogen. For the O(1D) + CH3OH reaction, the derived yields are in good agreement with the conclusions of previous experimental and theoretical works. For the O(1D) + CH3CN reaction, whose H-atom formation channels had not previously been investigated, electronic structure calculations of several new product formation channels are performed to explain the observed H-atom yields. These calculations demonstrate the barrierless and exothermic nature of the relevant exit channels, confirming that atomic hydrogen is also an important product of the O(1D) + CH3CN reaction.
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Affiliation(s)
- Kevin M Hickson
- Université Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33400 Talence, France
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2
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Synthesis of methanediol [CH 2(OH) 2]: The simplest geminal diol. Proc Natl Acad Sci U S A 2022; 119:2111938119. [PMID: 34969838 PMCID: PMC8740743 DOI: 10.1073/pnas.2111938119] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2021] [Indexed: 11/25/2022] Open
Abstract
Methanediol [CH2(OH)2] represents a pivotal atmospheric volatile organic compound and plays a fundamental role in aerosol growth. Although sought for decades, methanediol has never been identified due to the inherent dehydration tendency of two adjacent hydroxyl groups (OH) at the same carbon atom. Here, we prepare and identify methanediol via processing of low-temperature ices followed by sublimation into the gas phase. These findings open up a concept to synthesize and characterize unstable geminal diols—critical organic transients in Earth’s atmosphere. The excited state dynamics of oxygen may also lead to methanediol in methanol-rich interstellar ices in cold molecular clouds, followed by sublimation in star-forming regions and prospective detection of these reactive intermediates in the gas phase by radiotelescopes. Geminal diols—organic molecules carrying two hydroxyl groups at the same carbon atom—have been recognized as key reactive intermediates by the physical (organic) chemistry and atmospheric science communities as fundamental transients in the aerosol cycle and in the atmospheric ozonolysis reaction sequence. Anticipating short lifetimes and their tendency to fragment to water plus the aldehyde or ketone, free geminal diols represent one of the most elusive classes of organic reactive intermediates. Here, we afford an exceptional glance into the preparation of the previously elusive methanediol [CH2(OH)2] transient—the simplest geminal diol—via energetic processing of low-temperature methanol–oxygen ices. Methanediol was identified in the gas phase upon sublimation via isomer-selective photoionization reflectron time-of-flight mass spectrometry combined with isotopic substitution studies. Electronic structure calculations reveal that methanediol is formed via excited state dynamics through insertion of electronically excited atomic oxygen into a carbon–hydrogen bond of the methyl group of methanol followed by stabilization in the icy matrix. The first preparation and detection of methanediol demonstrates its gas-phase stability as supported by a significant barrier hindering unimolecular decomposition to formaldehyde and water. These findings advance our perception of the fundamental chemistry and chemical bonding of geminal diols and signify their role as an efficient sink of aldehydes and ketones in atmospheric environments eventually coupling the atmospheric chemistry of geminal diols and Criegee intermediates.
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Ji YT, Lee YP. Dynamics of Reaction CH 3CHI + O 2 Investigated via Infrared Emission of Products CO, CO 2, and OH. J Phys Chem A 2021; 125:8373-8385. [PMID: 34524829 DOI: 10.1021/acs.jpca.1c05610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction CH3CHI + O2 has been commonly employed in laboratories to produce a methyl-substituted Criegee intermediate CH3CHOO, but the detailed dynamics of this reaction remain unexplored. We carried out this reaction by irradiating a flowing mixture of CH3CHI2 (∼70 mTorr) and O2 (∼4 and 8 Torr) at 308 or 248 nm and observed infrared emission of the products with a step-scan Fourier-transform spectrometer. Upon irradiation at 248 nm with O2 ∼4 Torr, a Boltzmann distribution of CO (v ≤ 4, J ≤ 25) with average vibrational energy (12 ± 2) kJ mol-1 and of OH (v = 1, J ≤ 5.5) were observed and assigned to be produced from the decomposition of CH3C(O)OH* to form CO + CH3OH and OH + CH3CO, respectively. The observed broadband emission of CO2 was simulated with two vibrational distributions of average energies (42 ± 3) and (114 ± 6) kJ mol-1 and assigned to be produced from the decomposition of CH3C(O)OH* and (methyl dioxirane)*, respectively. The results upon irradiation of the sample at 308 nm are similar, likely indicating a small fraction of energy partition into these products and rapid thermalization of CH3CHI*. Compared with reaction CH2I + O2, the title reaction yielded products with much less internal excitation, consistent with the expectation that these observed products receive much less fraction of available energy upon fragmentation when an additional methyl moiety was present in the parent. The large-v component of CO observed in experiments of CH2I + O2 at 248 nm, produced from secondary reaction HCO + O2, was absent in this work because the corresponding secondary reaction CH3CO + O2 in decomposition of CH3CHOO* produces α-lactone + OH or H2CO + CO + OH.
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Affiliation(s)
- Ya-Tsang Ji
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan
| | - Yuan-Pern Lee
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan.,Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan.,Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106319, Taiwan
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Chen TY, Lee YP. Dynamics of the reaction CH 2I + O 2 probed via infrared emission of CO, CO 2, OH and H 2CO. Phys Chem Chem Phys 2020; 22:17540-17553. [PMID: 32808958 DOI: 10.1039/d0cp01940b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction CH2I + O2 has been widely employed recently for the production of the simplest Criegee intermediate CH2OO in laboratories, but the detailed dynamics of this reaction have been little explored. Infrared emission of several products of this reaction, initiated on irradiation of CH2I2 and O2 (∼8 Torr) in a flowing mixture at 308 or 248 nm, was recorded with a step-scan Fourier-transform spectrometer; possible routes of formation were identified according to the observed vibrational distribution of products and published theoretical potential-energy schemes. Upon irradiation at 308 nm, Boltzmann distributions of CO (v ≤ 5, J ≤ 19) with an average vibrational energy of 32 ± 3 kJ mol-1 and OH (v ≤ 3, J ≤ 5.5) with an average vibrational energy of 29 ± 4 kJ mol-1 were observed and assigned to the decomposition of HCOOH* to form CO + H2O and OH + HCO, respectively. The broadband emission of CO2 was simulated with two vibrational distributions of average energies (91 ± 4) and (147 ± 8) kJ mol-1 and assigned to be produced from the decomposition of HCOOH* and methylene bis(oxy), respectively. Upon irradiation of samples at 248 nm, the emission of OH and CO2 showed similar distributions with slightly greater energies, but the distribution of CO (v ≤ 11, J ≤ 19) became bimodal with average vibrational energies of (23 ± 4) and (107 ± 29) kJ mol-1, and branching (56 ± 5) : (44 ± 5). The additional large-v component is assigned to be produced from a secondary reaction HCO + O2 to form CO + HO2; HCO is a coproduct of OH. The branching between CO and OH is (50 ± 5) : (50 ± 5) at 308 nm and (64 ± 5) : (36 ± 4) at 248 nm, consistent with the mechanism according to which an additional channel to produce CO opens at 248 nm. Highly internally excited H2CO was also observed. With O2 at 16 Torr, the extrapolated nascent internal distributions are similar to those with O2 at 8 Torr except for a slight quenching effect.
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Affiliation(s)
- Ting-Yu Chen
- Department of Applied Chemistry and Institute of Molecular Science National Chiao Tung University, Hsinchu 30010, Taiwan.
| | - Yuan-Pern Lee
- Department of Applied Chemistry and Institute of Molecular Science National Chiao Tung University, Hsinchu 30010, Taiwan. and Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
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Ghoshal S, Pramanik A, Sarkar P. Theoretical Investigations on the Possibility of Prebiotic HCN Formation via O-Addition Reactions. J Phys Chem A 2020; 124:4782-4792. [PMID: 32401514 DOI: 10.1021/acs.jpca.0c02538] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Until now, reactions between methane photolysis products (CH3•, CH2) and active N atom or reactive NO radical are proposed as routes of HCN formation in the prebiotic Earth. Scientists think that the reducing atmosphere of primitive Earth was made of H2, He, N2, NO, CH4, H2O, CO2, etc., and there was no molecular oxygen. However, it has been evident from experiments that the vacuum ultraviolet (VUV) photolysis of CO2 can produce atomic oxygen. Therefore, it can be presumed that atomic oxygen was likely present in early Earth's atmosphere. Was there any impact of atomic oxygen in production of early atmospheric HCN for the emergence of life? To hunt for the answer, we have employed computational methods to study the mechanism and kinetics of CH3NO + O(1D) and CH2NO• + O(3P) addition reactions. Current study suggests that the addition of O(1D) into nitrosomethane (CH3NO) and the addition of O(3P) into nitrosomethylene radical (CH2NO•) can efficiently produce HCN through an effectively barrierless pathway. At STP, Bartis-Widom phenomenological loss rate coefficients of O(1D) and O(3P) are obtained as 2.47 × 10-12 and 4.67 × 10-11 cm3 molecule-1 s-1, respectively. We propose that addition reactions of atomic oxygen with CH3NO and CH2NO• might act as a potential source for early atmospheric HCN.
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Affiliation(s)
- Sourav Ghoshal
- Department of Chemistry, Visva-Bharati University, Santiniketan-731235, India
| | - Anup Pramanik
- Department of Chemistry, Visva-Bharati University, Santiniketan-731235, India.,Department of Chemistry, Sidho-Kanho-Birsha University, Purulia-723104, India
| | - Pranab Sarkar
- Department of Chemistry, Visva-Bharati University, Santiniketan-731235, India
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Wolf ME, Hoobler PR, Turney JM, Schaefer HF. Important features of the potential energy surface of the methylamine plus O( 1D) reaction. Phys Chem Chem Phys 2019; 21:24194-24205. [PMID: 31659355 DOI: 10.1039/c9cp05039f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This research presents an ab initio characterization of the potential energy surface for the methylamine plus 1D oxygen atom reaction, which may be relevant to interstellar chemistry. Geometries and harmonic vibrational frequencies were determined for all stationary points at the CCSD(T)/aug-cc-pVTZ level of theory. The focal point method along with several additive corrections was used to obtain reliable CCSDT(Q)/CBS potential energy surface features. Extensive conformational analysis and intrinsic reaction coordinate computations were performed to ensure accurate chemical connectivity of the stationary points. Five minima were determined to be possible products of this reaction and three novel transition states were found that were previously unreported or mislabeled in the literature. The pathways we present can be used to guide further searches for NH2 containing species in the interstellar medium.
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Affiliation(s)
- Mark E Wolf
- Center for Computational Quantum Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, USA.
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Kumar M, Anglada JM, Francisco JS. Role of Proton Tunneling and Metal-Free Organocatalysis in the Decomposition of Methanediol: A Theoretical Study. J Phys Chem A 2017; 121:4318-4325. [DOI: 10.1021/acs.jpca.7b01864] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Manoj Kumar
- Department
of Chemistry, University of Nebraska—Lincoln, Lincoln, Nebraska 68588, United States
| | - Josep M. Anglada
- Departament
de Química Biològica i Modelització Molecular, Institute of Advanced Chemistry of Catalonia, c/Jordi Girona 18, E-08034 Barcelona, Spain
| | - Joseph S. Francisco
- Department
of Chemistry, University of Nebraska—Lincoln, Lincoln, Nebraska 68588, United States
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Oliveira AM, Lehman JH, McCoy AB, Lineberger WC. Photoelectron spectroscopy of the hydroxymethoxide anion, H 2C(OH)O . J Chem Phys 2016; 145:124317. [PMID: 27782682 DOI: 10.1063/1.4963225] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report the negative ion photoelectron spectroscopy of the hydroxymethoxide anion, H2C(OH)O-. The photoelectron spectra show that 3.49 eV photodetachment produces two distinct electronic states of the neutral hydroxymethoxy radical (H2C(OH)O⋅). The H2C(OH)O⋅ ground state (X̃ 2A) photoelectron spectrum exhibits a vibrational progression consisting primarily of the OCO symmetric and asymmetric stretches, the OCO bend, as well as combination bands involving these modes with other, lower frequency modes. A high-resolution photoelectron spectrum aids in the assignment of several vibrational frequencies of the neutral H2C(OH)O⋅ radical, including an experimental determination of the H2C(OH)O⋅ 2ν12 overtone of the H-OCO torsional vibration as 220(10) cm-1. The electron affinity of H2C(OH)O⋅ is determined to be 2.220(2) eV. The low-lying à 2A excited state is also observed, with a spectrum that peaks ∼0.8 eV above the X̃ 2A state origin. The à 2A state photoelectron spectrum is a broad, partially resolved band. Quantum chemical calculations and photoelectron simulations aid in the interpretation of the photoelectron spectra. In addition, the gas phase acidity of methanediol is calculated to be 366(2) kcal mol-1, which results in an OH bond dissociation energy, D0(H2C(OH)O-H), of 104(2) kcal mol-1, using the experimentally determined electron affinity of the hydroxymethoxy radical.
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Affiliation(s)
- Allan M Oliveira
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Julia H Lehman
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Anne B McCoy
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - W Carl Lineberger
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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Huang SC, Nghia NT, Putikam R, Nguyen HMT, Lin MC, Tsuchiya S, Lee YP. Reaction dynamics of O(¹D) + HCOOD/DCOOH investigated with time-resolved Fourier-transform infrared emission spectroscopy. J Chem Phys 2015; 141:154313. [PMID: 25338902 DOI: 10.1063/1.4897418] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We investigated the reaction dynamics of O((1)D) towards hydrogen atoms of two types in HCOOH. The reaction was initiated on irradiation of a flowing mixture of O3 and HCOOD or DCOOH at 248 nm. The relative vibration-rotational populations of OH and OD (1 ≦ v ≦ 4, J ≤ 15) states were determined from time-resolved IR emission recorded with a step-scan Fourier-transform spectrometer. In the reaction of O((1)D) + HCOOD, the rotational distribution of product OH is nearly Boltzmann, whereas that of OD is bimodal. The product ratio [OH]/[OD] is 0.16 ± 0.05. In the reaction of O((1)D) + DCOOH, the rotational distribution of product OH is bimodal, but the observed OD lines are too weak to provide reliable intensities. The three observed OH/OD channels agree with three major channels of production predicted with quantum-chemical calculations. In the case of O((1)D) + HCOOD, two intermediates HOC(O)OD and HC(O)OOD are produced in the initial C-H and O-D insertion, respectively. The former undergoes further decomposition of the newly formed OH or the original OD, whereas the latter produces OD via direct decomposition. Decomposition of HOC(O)OD produced OH and OD with similar vibrational excitation, indicating efficient intramolecular vibrational relaxation, IVR. Decomposition of HC(O)OOD produced OD with greater rotational excitation. The predicted [OH]/[OD] ratio is 0.20 for O((1)D) + HCOOD and 4.08 for O((1)D) + DCOOH; the former agrees satisfactorily with experiments. We also observed the v3 emission from the product CO2. This emission band is deconvoluted into two components corresponding to internal energies E = 317 and 96 kJ mol(-1) of CO2, predicted to be produced via direct dehydration of HOC(O)OH and secondary decomposition of HC(O)O that was produced via decomposition of HC(O)OOH, respectively.
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Affiliation(s)
- Shang-Chen Huang
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - N T Nghia
- School of Chemical Engineering - Hanoi University of Science and Technology, Hanoi, Vietnam
| | - Raghunath Putikam
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Hue M T Nguyen
- Center for Computational Science and Faculty of Chemistry, Hanoi National University of Education, Hanoi, Vietnam
| | - M C Lin
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Soji Tsuchiya
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yuan-Pern Lee
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
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Nguyen TN, Putikam R, Lin MC. A novel and facile decay path of Criegee intermediates by intramolecular insertion reactions via roaming transition states. J Chem Phys 2015; 142:124312. [DOI: 10.1063/1.4914987] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Trong-Nghia Nguyen
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
- Department of Physical Chemistry, Hanoi University of Science and Technology, Hanoi, Vietnam
| | - Raghunath Putikam
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - M. C. Lin
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
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Huang YH, Chen JD, Hsu KH, Chu LK, Lee YP. Transient Infrared Absorption Spectra of Reaction Intermediates Detected with a Step-scan Fourier-transform Infrared Spectrometer. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.201300415] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hays BM, Widicus Weaver SL. Theoretical Examination of O(1D) Insertion Reactions to Form Methanediol, Methoxymethanol, and Aminomethanol. J Phys Chem A 2013; 117:7142-8. [DOI: 10.1021/jp400753r] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Brian M. Hays
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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