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McCarthy MC, Lee KLK, Stanton JF. Detection and structural characterization of nitrosamide H 2NNO: A central intermediate in deNO x processes. J Chem Phys 2017; 147:134301. [PMID: 28987087 DOI: 10.1063/1.4992097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The structure and bonding of H2NNO, the simplest N-nitrosamine, and a key intermediate in deNOx processes, have been precisely characterized using a combination of rotational spectroscopy of its more abundant isotopic species and high-level quantum chemical calculations. Isotopic spectroscopy provides compelling evidence that this species is formed promptly in our discharge expansion via the NH2 + NO reaction and is collisionally cooled prior to subsequent unimolecular rearrangement. H2NNO is found to possess an essentially planar geometry, an NNO angle of 113.67(5)°, and a N-N bond length of 1.342(3) Å; in combination with the derived nitrogen quadrupole coupling constants, its bonding is best described as an admixture of uncharged dipolar (H2N-N=O, single bond) and zwitterion (H2N+=N-O-, double bond) structures. At the CCSD(T) level, and extrapolating to the complete basis set limit, the planar geometry appears to represent the minimum of the potential surface, although the torsional potential of this molecule is extremely flat.
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Affiliation(s)
- Michael C McCarthy
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA and School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, Massachusetts 02138, USA
| | - Kin Long Kelvin Lee
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA and School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, Massachusetts 02138, USA
| | - John F Stanton
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712-0165, USA
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Bhasi P, Nhlabatsi ZP, Sitha S. Some possible channels for the N 2 formation and their probable effects on the interstellar elemental nitrogen partitioning: A computational study. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2017.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Fortenberry RC. The rovibrational nature of cis- and trans-HNNS: A possible nitrogen molecule progenitor. J Chem Phys 2017; 145:204302. [PMID: 27908132 DOI: 10.1063/1.4968036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The HNNS radical has been promoted recently as a viable intermediate in the interstellar creation of the spectroscopically elusive nitrogen molecule. Any confirmation of this pathway or utilizing HNNS as a tracer of N2 depends upon the ability to observe the radical intermediate whether in the laboratory or in the interstellar medium. Established and accurate quantum chemical procedures are employed here to produce spectroscopic constants, fundamental vibrational frequencies, and intensities that can be utilized for any possible detection of HNNS. While trans-HNNS is confirmed here to be 3.0 kcal/mol lower in energy than cis-HNNS, the latter will be more readily observed rotationally due to its significantly larger dipole moment. The N-N bond in cis-HNNS is stronger than in trans-HNNS, and earlier work has suggested that cis-HNNS is more useful in the creation of N2 from NH and NS. Hence, the detection of cis-HNNS may be of greater value anyway. Furthermore, the N-N stretch in either conformer is also exceptionally bright and will occur in the mid-infrared with nearly 30 cm-1 separating the fundamentals of the two conformers. Finally, the low isomerization barrier can be affected significantly upon deuteration also making ND an interesting consideration as a starting material in the interstellar formation of N2.
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Affiliation(s)
- Ryan C Fortenberry
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia 30460, USA
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Stoyanov ES, Stoyanova IV. Protonation of N2O and NO2 in a solid phase. Phys Chem Chem Phys 2017; 19:32733-32740. [DOI: 10.1039/c7cp04474g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Adsorption of gaseous N2O or NO2 on the acidic surface Brønsted centers of the strongest known solid acid, H(CHB11F11), results in formation of Brønsted and Lewis cationic superacids, NN–OH+ and NN+–OH.
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Affiliation(s)
- Evgenii S. Stoyanov
- Vorozhtsov Institute of Organic Chemistry
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russia
- Department of Natural Sciences
| | - Irina V. Stoyanova
- Vorozhtsov Institute of Organic Chemistry
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russia
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Crabtree KN, Martin-Drumel MA, Brown GG, Gaster SA, Hall TM, McCarthy MC. Microwave spectral taxonomy: A semi-automated combination of chirped-pulse and cavity Fourier-transform microwave spectroscopy. J Chem Phys 2016; 144:124201. [PMID: 27036440 DOI: 10.1063/1.4944072] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Because of its structural specificity, rotational spectroscopy has great potential as an analytical tool for characterizing the chemical composition of complex gas mixtures. However, disentangling the individual molecular constituents of a rotational spectrum, especially if many of the lines are entirely new or unknown, remains challenging. In this paper, we describe an empirical approach that combines the complementary strengths of two techniques, broadband chirped-pulse Fourier transform microwave spectroscopy and narrowband cavity Fourier transform microwave spectroscopy, to characterize and assign lines. This procedure, called microwave spectral taxonomy, involves acquiring a broadband rotational spectrum of a rich mixture, categorizing individual lines based on their relative intensities under series of assays, and finally, linking rotational transitions of individual chemical compounds within each category using double resonance techniques. The power of this procedure is demonstrated for two test cases: a stable molecule with a rich spectrum, 3,4-difluorobenzaldehyde, and products formed in an electrical discharge through a dilute mixture of C2H2 and CS2, in which spectral taxonomy has enabled the identification of propynethial, HC(S)CCH.
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Affiliation(s)
- Kyle N Crabtree
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA
| | - Marie-Aline Martin-Drumel
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | | - Taylor M Hall
- Coker College, Hartsville, South Carolina 29550, USA
| | - Michael C McCarthy
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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Bhasi P, Nhlabatsi ZP, Sitha S. Reaction between HN and SN: a possible channel for the interstellar formation of N2 and SH in the cold interstellar clouds. Phys Chem Chem Phys 2015; 17:32455-63. [PMID: 26594029 DOI: 10.1039/c5cp05190h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Using computational calculations the potential energy surface (PES) of the reaction between NH and NS has been analysed. The PES of the reaction shows the formation of two very stable species, HNSN and HNNS. Out of these two, HNNS which has the signature N-N linkage was found to be the most stable species in the PES. In view of the highly exothermic nature of the reaction surface, it has been proposed that these two species can possibly be detected in the interstellar space. For the first time it has also been shown that the reaction between the NH and NS can lead to the possible formation of N2via the isomer HNNS, and how the effect of tunnelling can make this reaction very much feasible, even under the extremely low temperature conditions prevailing in the interstellar medium. Based on the already reported results, a similar kind of behaviour for the NH + NO reaction surface has also been proposed. These dissociation reactions leading to the formation of N2 can be considered as potential secondary contributing channels while accounting for the total estimates of N2 in the interstellar medium, and thus HNNS as well as HNNO can be considered as stable reservoir molecules for interstellar N2. Besides the formation of N2, the formation of another astronomically important radical, SH in the cold interstellar clouds, has also been proposed.
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Affiliation(s)
- Priya Bhasi
- Department of Chemistry, University of Johannesburg, P.O. Box 524, Auckland Park, Johannesburg, South Africa 2006.
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Fortenberry RC, Huang X, McCarthy MC, Crawford TD, Lee TJ. Fundamental Vibrational Frequencies and Spectroscopic Constants of cis- and trans-HOCS, HSCO, and Isotopologues via Quartic Force Fields. J Phys Chem B 2014; 118:6498-510. [DOI: 10.1021/jp412362h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ryan C. Fortenberry
- Department of Chemistry, Georgia Southern University, Statesboro, Georgia 30460, United States
- NASA Ames Research Center, Moffett Field, California 94035-1000, United States
| | - Xinchuan Huang
- SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, California 94043, United States
| | - Michael C. McCarthy
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, United States
| | - T. Daniel Crawford
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Timothy J. Lee
- NASA Ames Research Center, Moffett Field, California 94035-1000, United States
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