Reaction Path of UV Photolysis of Matrix Isolated Acetyl Cyanide:  Formation and Identification of Ketenes, Zwitterion, and Keteneimine Intermediates

Guennoun, Zohra; Couturier-Tamburelli, Isabelle; Combes, S; Jp, Aycard; Piétri, Nathalie

doi:10.1021/jp0536854

Cited by 19 publications

(17 citation statements)

References 35 publications

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“…Similarly to our previous work 45 and to previous work concerning complexes involving ketene with HCN or HNC and the work of Kukolich et al 46 , we envisaged two plausible geometries for C 1 (Figure 3): the first one, called π-form, where the hydrogen atom of HCN is in interaction with the double bond of C 2 H 4 and a second one, a planar form (called ρ-form), with an interaction between the nitrogen atom of HCN and one hydrogen of C 2 H 4 .…”

Section: Infrared Spectroscopy Of Ethyl Cyanide 1 In Ar Matrixsupporting

confidence: 74%

Infrared study of matrix-isolated ethyl cyanide: simulation of the photochemistry in the atmosphere of Titan

Toumi

Piétri

Couturier-Tamburelli

2015

Phys. Chem. Chem. Phys.

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Low-temperature Ar matrix isolation has been carried out to investigate the infrared spectrum of ethyl cyanide (CH3CH2CN), a molecule present in the atmosphere of Titan. The λ > 120 nm and λ > 230 nm photolysis reactions of ethyl cyanide in an Ar matrix were also performed in order to compare the behaviour of this compound when it is submitted to high and low energetic radiations. These different wavelengths have been used with the aim to reproduce the radiation reaching the various parts of the atmosphere. Several photoproducts have been identified during photolysis such as vinyl cyanide (CH2[double bond, length as m-dash]CHCN), cyanoacetylene (HC3N), and ethylene/hydrogen cyanide (C2H4/HCN), ethylene/hydrogen isocyanide (C2H4/HNC), acetylene/hydrogen cyanide (C2H2/HCN), acetylene/hydrogen isocyanide (C2H2/HNC), and acetylene:methylenimine (C2H2:HNCH2) complexes. Ethyl isocyanide (CH3CH2NC) and a ketenimine form (CH3CH[double bond, length as m-dash]C[double bond, length as m-dash]NH) have been identified as well. Photoproduct identification and spectral assignments were done using previous studies and density functional theory (DFT) calculations with the B3LYP/cc-pVTZ basis set.

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Section: Infrared Spectroscopy Of Ethyl Cyanide 1 In Ar Matrixsupporting

confidence: 74%

Infrared study of matrix-isolated ethyl cyanide: simulation of the photochemistry in the atmosphere of Titan

Toumi

Piétri

Couturier-Tamburelli

2015

Phys. Chem. Chem. Phys.

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“…Thus, the photodissociation of CH 3 COCN occurs on the energetic ground state potential surface, different from the reaction mechanisms reported previously. [1][2][3][4][5][6][7][8][9][10] The ro-vibrational energy disposals in the HCN and CO fragments are determined by analyzing the corresponding high-resolution spectra. The measurements of O 2 dependence exclude the production possibility of these fragments via intersystem crossing.…”

Section: Discussionmentioning

confidence: 99%

“…In contrast to the gas-phase decomposition, Guennoun et al 10 investigated UV photolysis of acetyl cyanide trapped in an argon matrix at 10 K using Fourier-transform infrared spectroscopy (FTIR). After several hours irradiation at either λ > 180 nm or λ > 230 nm, the first photoreaction product was acetyl isocyanide, whereas CH 3 CN and CH 3 NC were obtained as final products at λ > 180 nm.…”

Section: Introductionmentioning

confidence: 99%

Gas-phase photodissociation of CH3COCN at 308 nm by time-resolved Fourier-transform infrared emission spectroscopy

Yeh

Chao

Tsai

et al. 2012

The Journal of Chemical Physics

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By using time-resolved Fourier-transform infrared emission spectroscopy, the fragments of HCN(v = 1, 2) and CO(v = 1-3) are detected in one-photon dissociation of acetyl cyanide (CH(3)COCN) at 308 nm. The S(1)(A(")), (1)(n(O), π(∗) (CO)) state at 308 nm has a radiative lifetime of 0.46 ± 0.01 μs, long enough to allow for Ar collisions that induce internal conversion and enhance the fragment yields. The rate constant of Ar collision-induced internal conversion is estimated to be (1-7) × 10(-12) cm(3) molecule(-1) s(-1). The measurements of O(2) dependence exclude the production possibility of these fragments via intersystem crossing. The high-resolution spectra of HCN and CO are analyzed to determine the ro-vibrational energy deposition of 81 ± 7 and 32 ± 3 kJ∕mol, respectively. With the aid of ab initio calculations, a two-body dissociation on the energetic ground state is favored leading to HCN + CH(2)CO, in which the CH(2)CO moiety may further undergo secondary dissociation to release CO. The production of CO(2) in the reaction with O(2) confirms existence of CH(2) and a secondary reaction product of CO. The HNC fragment is identified but cannot be assigned, as restricted to a poor signal-to-noise ratio. Because of insufficient excitation energy at 308 nm, the CN and CH(3) fragments that dominate the dissociation products at 193 nm are not detected.

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“…In this spectrum, valence and Rydberg transitions, converging to the first ionization energy at 11.21 eV, 13 are identified. For the sake of completeness, we mention a matrix isolation study 14 where AC is trapped in an argon matrix and irradiated at wavelengths of either λ > 180 or λ > 230 nm. Several products are identified in matrix by IR spectroscopy, among them acetyl isocyanide CH 3 C(O)NC, ketene:HCN and ketene:HNC complexes, as well as methyl cyanide (CH 3 CN) and methyl isocyanide (CH 3 NC).…”

Section: Introductionmentioning

confidence: 99%

VUV photoionization and dissociative photoionization of the prebiotic molecule acetyl cyanide: Theory and experiment

Bellili

Schwell

Bénilan

et al. 2014

The Journal of Chemical Physics

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The present combined theoretical and experimental investigation concerns the single photoionization of gas-phase acetyl cyanide and the fragmentation pathways of the resulting cation. Acetyl cyanide (AC) is inspired from both the chemistry of cyanoacetylene and the Strecker reaction which are thought to be at the origin of medium sized prebiotic molecules in the interstellar medium. AC can be formed by reaction from cyanoacetylene and water but also from acetaldehyde and HCN or the corresponding radicals. In view of the interpretation of vacuum ultraviolet (VUV) experimental data obtained using synchrotron radiation, we explored the ground potential energy surface (PES) of acetyl cyanide and of its cation using standard and recently implemented explicitly correlated methodologies. Our PES covers the regions of tautomerism (between keto and enol forms) and of the lowest fragmentation channels. This allowed us to deduce accurate thermochemical data for this astrobiologically relevant molecule. Unimolecular decomposition of the AC cation turns out to be very complex. The implications for the evolution of prebiotic molecules under VUV irradiation are discussed.

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Reaction Path of UV Photolysis of Matrix Isolated Acetyl Cyanide: Formation and Identification of Ketenes, Zwitterion, and Keteneimine Intermediates

Cited by 19 publications

References 35 publications

Infrared study of matrix-isolated ethyl cyanide: simulation of the photochemistry in the atmosphere of Titan

Infrared study of matrix-isolated ethyl cyanide: simulation of the photochemistry in the atmosphere of Titan

Gas-phase photodissociation of CH3COCN at 308 nm by time-resolved Fourier-transform infrared emission spectroscopy

VUV photoionization and dissociative photoionization of the prebiotic molecule acetyl cyanide: Theory and experiment

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