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Hockey EK, McLane N, Vlahos K, McCaslin LM, Dodson LG. Matrix-formation dynamics dictate methyl nitrite conformer abundance. J Chem Phys 2024; 160:094303. [PMID: 38436440 DOI: 10.1063/5.0188433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 01/31/2024] [Indexed: 03/05/2024] Open
Abstract
Methyl nitrite has two stable conformational isomers resulting from rotation about the primary C-O-N-O dihedral angle: cis-CH3ONO and trans-CH3ONO, with cis being more stable by ∼5 kJ/mol. The barrier to rotational interconversion (∼45 kJ/mol) is too large for isomerization to occur under ambient conditions. This paper presents evidence of a change in conformer abundance when dilute CH3ONO is deposited onto a cold substrate; the relative population of the freshly deposited cis conformer is seen to increase compared to its gas-phase abundance, measured by in situ infrared spectroscopy. We observe abundance changes depending on the identity of the bath gas (N2, Ar, and Xe) and deposition angle. The observations indicate that the surface properties of the growing matrix influence conformer abundance-contrary to the widely held assumption that conformer abundance in matrices reflects gas-phase abundance. We posit that differences in the angle-dependent host-gas deposition dynamics affect the growing surfaces, causing changes in conformer abundances. Quantum chemistry calculations of the binding energies between CH3ONO and a single bath-gas component reveal that significant energetic stabilization is not observed in 1:1 complexes of N2:CH3ONO, Ar:CH3ONO, or Xe:CH3ONO. From our results, we conclude that the growing surface plays a significant role in trapping cis-CH3ONO more effectively than trans-CH3ONO, likely because cis-CH3ONO is more compact. Taken together, the observations highlight the necessity for careful characterization of conformers in matrix-isolated systems, emphasizing a need for further study into the deposition dynamics and surface structure of chemically inert matrices.
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Affiliation(s)
- Emily K Hockey
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - Nathan McLane
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - Korina Vlahos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | | | - Leah G Dodson
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
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Zhu B, Zeng X. 3-Fluoro-2 H-azirine: Generation, Characterization, and Photochemistry. J Phys Chem A 2023; 127:10591-10599. [PMID: 38063135 DOI: 10.1021/acs.jpca.3c06076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
The elusive 3-fluoro-2H-azirine, cyclic NCH2CF, has been generated through the stepwise decomposition of the acryloyl azide CH2CFC(O)N3 in an N2-matrix at 10 K. The characterization of cyclic NCH2CF with matrix-isolation IR spectroscopy is supported by 15N isotope labeling and the calculations with density functional theory (DFT) at the B3LYP/6-311++G(3df,3pd) level of theory. Upon irradiation at 193 nm, cyclic NCH2CF undergoes ring opening by forming the more stable nitrile isomer CH2FCN. In contrast to the photodecomposition reactions, the high-vacuum flash pyrolysis of CH2CFC(O)N3 in the gas phase at 500 °C yields the Curtius rearrangement product CH2CFNCO along with secondary fragmentation to the atmospherically relevant fluorocarbonyl radical (FCO) and cyanomethyl radical (CH2CN). Calculations on the potential energy profile for the decomposition reactions of CH2CFC(O)N3 demonstrate that the excessive energy, arising from the highly exothermic Curtius rearrangement of the azide, plays a key role in driving further dissociation reactions of CH2CFNCO by overcoming the formidable barriers (>50 kcal mol-1) under the pyrolysis conditions.
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Affiliation(s)
- Bifeng Zhu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China
| | - Xiaoqing Zeng
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China
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Liu C, Chen Y, Guo G, Zhao Q, Jiang H, Wu K, Peng Q, Chen Y, Fang D, Shen B, Shen H, Wu D, Sun H. Interpretable Machine Learning Model for Predicting Interaction Energies between Dimethyl Sulfide and Potential Absorbing Solvents. Ind Eng Chem Res 2023. [DOI: 10.1021/acs.iecr.2c04559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Affiliation(s)
- Chuanlei Liu
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yuxiang Chen
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Guanchu Guo
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Qiyue Zhao
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Hao Jiang
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Kongguo Wu
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Qilong Peng
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yu Chen
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Diyi Fang
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Benxian Shen
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
- International Joint Research Center of Green Energy Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Haitao Shen
- International Joint Research Center of Green Energy Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Di Wu
- Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, Washington 99163, United States
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99163, United States
- Materials Science and Engineering, Washington State University, Pullman, Washington 99163, United States
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Hui Sun
- School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
- International Joint Research Center of Green Energy Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
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Fortenberry RC, McMahon RJ, Kaiser RI. 10 Years of the ACS PHYS Astrochemistry Subdivision. J Phys Chem A 2022; 126:6571-6574. [PMID: 36172712 DOI: 10.1021/acs.jpca.2c06091] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryan C Fortenberry
- Department of Chemistry and Biochemistry, University of Mississippi, 322 Coulter Hall, University, Mississippi 38677-1848, United States
| | - Robert J McMahon
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
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