Gas-phase pyrolysis of <i>trans</i> 3-pentenenitrile: competition between direct and isomerization-mediated dissociation

Mishra, Piyush; Fritz, Sean; Herbers, Sven; Mebel, Alexander M.; Zwier, Timothy S.

doi:10.1039/d1cp00104c

Cited by 5 publications

(16 citation statements)

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“…The latter group of molecules that we have been studying are nitrile-containing structural isomers of pyridine (C 5 H 5 N) (Figure ). Several of these species are likely to be involved in complex, astrochemically relevant processes , and have been detected in harsh reaction environments. − Expanding the family of pyridine isomers facilitates future investigations of the reactivity of these small molecules and astronomical searches for these species in extraterrestrial environments. Astronomical detections of any of the molecules from either group would be of fundamental interest and could illuminate new astrochemical pathways toward complex aromatic species.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Purification, and Rotational Spectroscopy of (Cyanomethylene)Cyclopropane—An Isomer of Pyridine

et al. 2021

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The gas-phase rotational spectrum of (cyanomethylene)cyclopropane, (CH 2 ) 2 CCHCN, generated by a Wittig reaction between the hemiketal of cyclopropanone and (cyanomethylene)triphenylphosphorane, is presented for the first time. This small, highly polar nitrile is a cyclopropylcontaining structural isomer of pyridine. The rotational spectra of the ground state and two vibrationally excited states were observed, analyzed, and least-squares fit from 130 to 360 GHz. Over 3900 R-, P-, and Q-branch, ground-state rotational transitions were fit to low-error, partial octic, A-and S-reduced Hamiltonians, providing precise determinations of the spectroscopic constants. The two lowest-energy vibrationally excited states, ν 17 and ν 27 , form a Coriolis-coupled dyad displaying small aand b-type resonances. Transitions for these two states were measured and least-squares fit to a two-state, partial octic, A-reduced Hamiltonian in the I r representation with nine Coriolis-coupling terms (G a , G a J , G a K , G a JJ , F bc , F bc J , F bc K , G b , and G b J). The observation of many resonant transitions and nine nominal interstate transitions enabled a very accurate and precise energy difference between ν 17 and ν 27 to be determined: ΔE 17,27 = 29.8975453 (33) cm −1 . The spectroscopic constants presented herein provide the foundation for future astronomical searches for (cyanomethylene)cyclopropane.

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Section: Introductionmentioning

confidence: 99%

Synthesis, Purification, and Rotational Spectroscopy of (Cyanomethylene)Cyclopropane—An Isomer of Pyridine

et al. 2021

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“…Data distribution plot for the least-squares fit of spectroscopic data from the current work (black and blue), measurements from McCarthy et al (purple and red, due to the high relative error), and measurements from Mishra et al (green) for the vibrational ground state of s-trans - Z -1-cyano-1,3-butadiene. Circles indicate Q- and R-branch transitions.…”

Section: Results and Discussionmentioning

confidence: 94%

“…In our least-squares fits, we assume a uniform frequency measurement uncertainty of 50 kHz for our data. Transitions from McCarthy et al use an uncertainty of 2 kHz, and those from Mishra et al use 60 kHz.…”

Section: Materials and Methodsmentioning

confidence: 99%

“…Zwier and co-workers investigated the gas-phase pyrolysis of trans -3-pentenenitrile, which results in dehydrogenation to afford Z -1-cyano-1,3-butadiene, among many products (Figure b). Notably, pyridine was not detected, despite being lower in energy than the detected cyanobutadiene isomer . The spectroscopic assignments in both of these experiments were made on the basis of data reported herein.…”

Section: Introductionmentioning

confidence: 94%

“…(a) Discharge of benzene and nitrogen produces E -1-cyano-1,3-butadiene and Z -1-cyano-1,3-butadiene . (b) Pyrolysis of 1-cyano-2-butene produces Z -1-cyano-1,3-butadiene …”

Section: Introductionmentioning

confidence: 99%

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Rotational Spectra of Three Cyanobutadiene Isomers (C₅H₅N) of Relevance to Astrochemistry and Other Harsh Reaction Environments

et al. 2021

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Three cyanobutadiene isomers have been synthesized and their rotational spectra analyzed in the 130–375 GHz frequency range. These species, which are close analogues of known interstellar molecules and are isomers of the heterocyclic aromatic molecule pyridine (C5H5N), offer the opportunity of revealing important insights concerning the chemistry in astronomical environments. The s-trans conformers of E-1-cyano-1,3-butadiene and Z-1-cyano-1,3-butadiene are observed, while both the anti-clinal and syn-periplanar conformers of 4-cyano-1,2-butadiene are evident in the rotational spectra. Over 1000 transitions for s-trans-Z-1-cyano-1,3-butadiene and for syn-periplanar-4-cyano-1,2-butadiene are fit to an octic, distorted-rotor Hamiltonian with low uncertainty (<50 kHz). Although neither s-trans-E-1-cyano-1,3-butadiene nor anti-clinal-4-cyano-1,2-butadiene can be fully treated with a distorted-rotor Hamiltonian in this frequency range, we provide herein minimally perturbed, single-state least-squares fits of over 1000 transitions for each species, yielding sets of spectroscopic constants that are expected to enable accurate prediction of high-intensity transitions at frequencies up to 370 GHz for both isomers. The assigned transitions and spectroscopic constants for these cyanobutadienes have already enabled the identification of two isomers in harsh reaction environments and should be sufficient to enable their identification in astronomical environments by radio astronomy.

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Synthesis, Purification, and Rotational Spectroscopy of 1-Cyanocyclobutene (C₅H₅N)

et al. 2022

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The rotational spectrum of 1-cyanocyclobutene from 130 to 360 GHz has been observed, assigned, and least-squares fit for the ground state and the two lowest-energy vibrationally excited states. Synthesis by UV photochemical dimerization of acrylonitrile and subsequent base-catalyzed dehydrocyanation affords a highly pure sample, yielding several thousand observable rotational transitions for this small organic nitrile. Over 2500 a-type, R-branch transitions of the ground state have been least-squares fit to low error with partial-octic A- and S-reduced Hamiltonians, providing precise determinations of the corresponding spectroscopic constants. In both reductions, computed spectroscopic constants are in close agreement with their experimentally determined counterparts. Two vibrationally excited states (ν27 and ν17) form a Coriolis-coupled dyad, displaying many a-type and b-type local resonances and related nominal interstate transitions. Somewhat unexpectedly, despite the very small permanent b-axis dipole moment, a number of b-type transitions could be observed for the ν17 state; this is explained in terms of state mixing by the Coriolis perturbations. Over 2200 transitions for each of these states have been least-squares fit to a low-error, two-state, partial-octic, A-reduced Hamiltonian with nine Coriolis-coupling terms (G a , Ga J , G a K , G a JJ , F bc , F bc K , G b , G b J , and F ac ). The availability of so many observed rotational transitions, including resonant transitions and nominal interstate transitions, enables a very accurate and precise determination of the energy difference (ΔE 27,17 = 14.0588093 (43) cm–1) between ν27 and ν17. The spectroscopic constants presented herein provide a starting point for future astronomical searches for 1-cyanocyclobutene.

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Gas-phase pyrolysis of trans 3-pentenenitrile: competition between direct and isomerization-mediated dissociation

Abstract: The flash pyrolysis of trans 3-pentenenitrile (3-PN, CH3-CH=CH-CH2-CN) was studied by combining the results of VUV photoionization mass spectra with broadband microwave spectra recorded as a function of the temperature...

Cited by 5 publications

References 46 publications

Synthesis, Purification, and Rotational Spectroscopy of (Cyanomethylene)Cyclopropane—An Isomer of Pyridine

Synthesis, Purification, and Rotational Spectroscopy of (Cyanomethylene)Cyclopropane—An Isomer of Pyridine

Rotational Spectra of Three Cyanobutadiene Isomers (C₅H₅N) of Relevance to Astrochemistry and Other Harsh Reaction Environments

Synthesis, Purification, and Rotational Spectroscopy of 1-Cyanocyclobutene (C₅H₅N)

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Gas-phase pyrolysis of trans 3-pentenenitrile: competition between direct and isomerization-mediated dissociation

Abstract: The flash pyrolysis of trans 3-pentenenitrile (3-PN, CH3-CH=CH-CH2-CN) was studied by combining the results of VUV photoionization mass spectra with broadband microwave spectra recorded as a function of the temperature...

Cited by 5 publications

References 46 publications

Synthesis, Purification, and Rotational Spectroscopy of (Cyanomethylene)Cyclopropane—An Isomer of Pyridine

Synthesis, Purification, and Rotational Spectroscopy of (Cyanomethylene)Cyclopropane—An Isomer of Pyridine

Rotational Spectra of Three Cyanobutadiene Isomers (C5H5N) of Relevance to Astrochemistry and Other Harsh Reaction Environments

Synthesis, Purification, and Rotational Spectroscopy of 1-Cyanocyclobutene (C5H5N)

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Rotational Spectra of Three Cyanobutadiene Isomers (C₅H₅N) of Relevance to Astrochemistry and Other Harsh Reaction Environments

Synthesis, Purification, and Rotational Spectroscopy of 1-Cyanocyclobutene (C₅H₅N)