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Nakamura T, Dangi BB, Wu L, Zhang Y, Schoendorff G, Gordon MS, Yang DS. Spin-orbit coupling of electrons on separate lanthanide atoms of Pr2O2 and its singly charged cation. J Chem Phys 2023; 159:244303. [PMID: 38131482 DOI: 10.1063/5.0185579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Although it plays a critical role in the photophysics and catalysis of lanthanides, spin-orbit coupling of electrons on individual lanthanide atoms in small clusters is not well understood. The major objective of this work is to probe such coupling of the praseodymium (Pr) 4f and 6s electrons in Pr2O2 and Pr2O2+. The approach combines mass-analyzed threshold ionization spectroscopy and spin-orbit multiconfiguration second-order quasi-degenerate perturbation theory. The energies of six ionization transitions are precisely measured; the adiabatic ionization energy of the neutral cluster is 38 045 (5) cm-1. Most of the electronic states involved in these transitions are identified as spin-orbit coupled states consisting of two or more electron spins. The electron configurations of these states are 4f46s2 for the neutral cluster and 4f46s for the singly charged cation, both in planar rhombus-type structures. The spin-orbit splitting due to the coupling of the electrons on the separate Pr atoms is on the order of hundreds of wavenumbers.
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Affiliation(s)
- Taiji Nakamura
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, Iowa 50011-3111, USA
- Institute for Materials Chemistry and Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Beni B Dangi
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
| | - Lu Wu
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
| | - Yuchen Zhang
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
| | - George Schoendorff
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, Iowa 50011-3111, USA
- Propellants Branch, Rocket Propulsion Division, Aerospace Systems Directorate, Air Force Research Laboratory, AFRL/RQRP, Edwards Air Force Base, California 93524, USA
| | - Mark S Gordon
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, Iowa 50011-3111, USA
| | - Dong-Sheng Yang
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
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2
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Lynn MO, Ologunagba D, Dangi BB, Kattel S. Density functional theory study of bulk properties of transition metal nitrides. Phys Chem Chem Phys 2023; 25:5156-5163. [PMID: 36723016 DOI: 10.1039/d2cp06082e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Density functional theory (DFT) calculations are performed to compute the lattice constants, formation energies and vacancy formation energies of transition metal nitrides (TMNs) for transition metals (TM) ranging from 3d-5d series. The results obtained using six different DFT exchange and correlation potentials (LDA, AM05, BLYP, PBE, rPBE, and PBEsol) show that the experimental lattice constants are best predicted by rPBE, while the values obtained using AM05, PBE, rPBE and PBEsol lie between the LDA and BLYP calculated values. A linear relationship is observed between the lattice constants and formation energies with the mean radii of TM and the difference in the electronegativity of TM and N in TMNs, respectively. Our calculated vacancy formation energies, in general, show that N-vacancies are more favorable than TM-vacancies in most TMNs. We observe that N-vacancy formation energies are linearly correlated with the calculated bulk formation energies indicating that TMNs with large negative formation energies are less susceptible to the formation of N-vacancies. Thus, our results from this extensive DFT study not only provide a systematic comparison of various DFT functionals in calculating the properties of TMNs but also serve as reference data for the computation-driven experimental design of materials.
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Affiliation(s)
- Michael O Lynn
- Department of Physics, Florida Agricultural and Mechanical University, Tallahassee, FL, 32307, USA.
| | - Damilola Ologunagba
- Department of Physics, Florida Agricultural and Mechanical University, Tallahassee, FL, 32307, USA.
| | - Beni B Dangi
- Department of Chemistry, Florida Agricultural and Mechanical University, Tallahassee, FL, USA, 32307.
| | - Shyam Kattel
- Department of Physics, Florida Agricultural and Mechanical University, Tallahassee, FL, 32307, USA.
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He C, Thomas AM, Dangi BB, Yang T, Kaiser RI, Lee HC, Sun BJ, Chang AHH. Formation of the Elusive Silylenemethyl Radical (HCSiH 2; X 2B 2) via the Unimolecular Decomposition of Triplet Silaethylene (H 2CSiH 2; a 3A″). J Phys Chem A 2022; 126:3347-3357. [PMID: 35584043 DOI: 10.1021/acs.jpca.2c01853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated the formation of small organosilicon molecules─potential precursors to silicon-carbide dust grains ejected by dying carbon-rich asymptotic giant branch stars─in the gas phase via the reaction of atomic carbon (C) in its 3P electronic ground state with silane (SiH4; X1A1) using the crossed molecular beams technique. The reactants collided under single collision conditions at a collision energy of 13.0 ± 0.2 kJ mol-1, leading to the formation of the silylenemethyl radical (HCSiH2; X2B2) via the unimolecular decomposition of triplet silaethylene (H2CSiH2; a3A″). The silaethylene radical was formed via hydrogen migration of the triplet silylmethylene (HCSiH3; X3A″) radical, which in turn was identified as the initial collision complex accessed via the barrierless insertion of atomic carbon into the silicon-hydrogen bond of silane. Our results mark the first observation of the silylenemethyl radical, where previously only its thermodynamically more stable methylsilylidyne (CH3Si; X2A″) and methylenesilyl (CH2SiH; X2A') isomers were observed in low-temperature matrices. Considering the abundance of silane and the availability of atomic carbon in carbon-rich circumstellar environments, our results suggest that future astrochemical models should be updated to include contributions from small saturated organosilicon molecules as potential precursors to pure gaseous silicon-carbides and ultimately to silicon-carbide dust.
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Affiliation(s)
- Chao He
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Beni B Dangi
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Tao Yang
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Huan-Cheng Lee
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Bing-Jian Sun
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Agnes H H Chang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
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Dangi BB, Dickerson DJ. Design and Performance of an Acoustic Levitator System Coupled with a Tunable Monochromatic Light Source and a Raman Spectrometer for In Situ Reaction Monitoring. ACS Omega 2021; 6:10447-10453. [PMID: 34056197 PMCID: PMC8153768 DOI: 10.1021/acsomega.1c00921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
The design and performance of a custom-built reaction chamber combined with an acoustic levitator, a tunable monochromatic light source, and a Raman spectrometer are reported. The pressure-compatible reaction chamber was vacuum-tested and coupled with the acoustic levitator that allows contactless sample handling, free of contingent sample requirements such as charge and refractive index. The calibration and performance of the Raman spectrometer was studied utilizing gated detection and three different gratings that can be interchanged within seconds for a desired resolution and photon collection range. A wide range of 186-5000 cm-1 Raman shift, with a small uncertainty of ±2 cm-1, can be recorded covering a complete vibrational range in chemical reaction monitoring. The gating of the detector allowed operation under the room light and filtration of unwanted sample fluorescence. The in situ reaction perturbation and monitoring of physical and chemical changes of samples by the Raman system were demonstrated by degradation of polystyrene by monochromatic UV light and photobleaching of a potato slice by visible light. This instrument provides a versatile platform for in situ investigation of surface reactions, without external support structures and under controlled pressure and radiation conditions, relevant to various disciplines such as materials science, astrochemistry, and molecular biology.
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Affiliation(s)
- Beni B. Dangi
- Department of Chemistry, Florida
Agricultural and Mechanical University, Tallahassee, Florida 32307, United States
| | - Daniel J. Dickerson
- Department of Chemistry, Florida
Agricultural and Mechanical University, Tallahassee, Florida 32307, United States
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Thomas AM, Dangi BB, Yang T, Kaiser RI, Sun BJ, Chou TJ, Chang AH. A crossed molecular beams investigation of the reactions of atomic silicon (Si(3P)) with C4H6 isomers (1,3-butadiene, 1,2-butadiene, and 1-butyne). Chem Phys 2019. [DOI: 10.1016/j.chemphys.2019.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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7
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Thomas AM, Dangi BB, Yang T, Tarczay G, Kaiser RI, Sun BJ, Chen SY, Chang AHH, Nguyen TL, Stanton JF, Mebel AM. Directed Gas-Phase Formation of the Germaniumsilylene Butterfly Molecule (Ge(μ-H 2)Si). J Phys Chem Lett 2019; 10:1264-1271. [PMID: 30817157 DOI: 10.1021/acs.jpclett.9b00284] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The hitherto elusive dibridged germaniumsilylene molecule (Ge(μ-H2)Si) has been formed for the first time via the bimolecular gas-phase reaction of ground-state germanium atoms (Ge) with silane (SiH4) under single-collision conditions. Merged with state-of-the-art electronic structure calculations, the reaction was found to proceed through initial formation of a van der Waals complex in the entrance channel, insertion of the germanium into a silicon-hydrogen bond, intersystem crossing from the triplet to the singlet surface, hydrogen migrations, and eventually elimination of molecular hydrogen via a tight exit transition state, leading to the germaniumsilylene "butterfly". This investigation provides an extraordinary peek at the largely unknown silicon-germanium chemistry on the molecular level and sheds light on the essential nonadiabatic reaction dynamics of germanium and silicon, which are quite distinct from those of the isovalent carbon system, thus offering crucial insights that reveal exotic chemistry and intriguing chemical bonding in the germanium-silicon system on the most fundamental, microscopic level.
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Affiliation(s)
- Aaron M Thomas
- Department of Chemistry , University of Hawai'i at Manoa , Honolulu , Hawaii 96822 , United States
| | - Beni B Dangi
- Department of Chemistry , University of Hawai'i at Manoa , Honolulu , Hawaii 96822 , United States
| | - Tao Yang
- Department of Chemistry , University of Hawai'i at Manoa , Honolulu , Hawaii 96822 , United States
| | - György Tarczay
- Department of Chemistry , University of Hawai'i at Manoa , Honolulu , Hawaii 96822 , United States
| | - Ralf I Kaiser
- Department of Chemistry , University of Hawai'i at Manoa , Honolulu , Hawaii 96822 , United States
| | - Bing-Jian Sun
- Department of Chemistry , National Dong Hwa University , Shoufeng , Hualien 974 , Taiwan
| | - Si-Ying Chen
- Department of Chemistry , National Dong Hwa University , Shoufeng , Hualien 974 , Taiwan
| | - Agnes H H Chang
- Department of Chemistry , National Dong Hwa University , Shoufeng , Hualien 974 , Taiwan
| | - Thanh L Nguyen
- Quantum Theory Project, Department of Chemistry and Physics , University of Florida , Gainesville , Florida 32611 , United States
| | - John F Stanton
- Quantum Theory Project, Department of Chemistry and Physics , University of Florida , Gainesville , Florida 32611 , United States
| | - Alexander M Mebel
- Florida International University , Miami , Florida 33199 , United States
- Samara University , Samara 443086 , Russia
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8
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Thomas AM, Dangi BB, Yang T, Kaiser RI, Lin L, Chou TJ, Chang AHH. Are Nonadiabatic Reaction Dynamics the Key to Novel Organosilicon Molecules? The Silicon (Si( 3P))-Dimethylacetylene (C 4H 6(X 1A 1g)) System as a Case Study. J Phys Chem Lett 2018; 9:3340-3347. [PMID: 29846075 DOI: 10.1021/acs.jpclett.8b01422] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The bimolecular gas phase reaction of ground-state silicon (Si; 3P) with dimethylacetylene (C4H6; X1A1g) was investigated under single collision conditions in a crossed molecular beams machine. Merged with electronic structure calculations, the data propose nonadiabatic reaction dynamics leading to the formation of singlet SiC4H4 isomer(s) and molecular hydrogen (H2) via indirect scattering dynamics along with intersystem crossing (ISC) from the triplet to the singlet surface. The reaction may lead to distinct energetically accessible singlet SiC4H4 isomers (1p8-1p24) in overall exoergic reaction(s) (-107-20+12 kJ mol-1). All feasible reaction products are either cyclic, carry carbene analogous silylene moieties, or carry C-Si-H or C-Si-C bonds that would require extensive isomerization from the initial collision complex(es) to the fragmenting singlet intermediate(s). The present study demonstrates the first successful crossed beams study of an exoergic reaction channel arising from bimolecular collisions of silicon, Si(3P), with a hydrocarbon molecule.
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Affiliation(s)
- Aaron M Thomas
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Beni B Dangi
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Tao Yang
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Ralf I Kaiser
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Lin Lin
- Department of Chemistry , National Dong Hwa University , Hualien 974 , Taiwan
| | - Tzu-Jung Chou
- Department of Chemistry , National Dong Hwa University , Hualien 974 , Taiwan
| | - Agnes H H Chang
- Department of Chemistry , National Dong Hwa University , Hualien 974 , Taiwan
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9
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Yang T, Thomas AM, Dangi BB, Kaiser RI, Mebel AM, Millar TJ. Directed gas phase formation of silicon dioxide and implications for the formation of interstellar silicates. Nat Commun 2018; 9:774. [PMID: 29472549 PMCID: PMC5823853 DOI: 10.1038/s41467-018-03172-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 01/24/2018] [Indexed: 11/12/2022] Open
Abstract
Interstellar silicates play a key role in star formation and in the origin of solar systems, but their synthetic routes have remained largely elusive so far. Here we demonstrate in a combined crossed molecular beam and computational study that silicon dioxide (SiO2) along with silicon monoxide (SiO) can be synthesized via the reaction of the silylidyne radical (SiH) with molecular oxygen (O2) under single collision conditions. This mechanism may provide a low-temperature path-in addition to high-temperature routes to silicon oxides in circumstellar envelopes-possibly enabling the formation and growth of silicates in the interstellar medium necessary to offset the fast silicate destruction.
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Affiliation(s)
- Tao Yang
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI, 96822, USA
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200062, China
| | - Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI, 96822, USA
| | - Beni B Dangi
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI, 96822, USA
- Department of Chemistry, Florida Agricultural and Mechanical University, Tallahassee, FL, 32307, USA
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI, 96822, USA.
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, 33199, USA.
| | - Tom J Millar
- Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK.
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10
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Yang T, Dangi BB, Kaiser RI, Chao K, Sun B, Chang AHH, Nguyen TL, Stanton JF. Inside Back Cover: Gas‐Phase Formation of the Disilavinylidene (H
2
SiSi) Transient (Angew. Chem. Int. Ed. 5/2017). Angew Chem Int Ed Engl 2017. [DOI: 10.1002/anie.201612283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Tao Yang
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
| | - Beni B. Dangi
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
- Department of Chemistry Florida A&M University Tallahassee FL 32307 USA
| | - Ralf I. Kaiser
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
| | - Kang‐Heng Chao
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Bing‐Jian Sun
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Agnes H. H. Chang
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Thanh Lam Nguyen
- Department of Chemistry University of Texas at Austin Austin TX 78712 USA
| | - John F. Stanton
- Department of Chemistry University of Texas at Austin Austin TX 78712 USA
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Yang T, Dangi BB, Kaiser RI, Chao K, Sun B, Chang AHH, Nguyen TL, Stanton JF. Innenrücktitelbild: Gas‐Phase Formation of the Disilavinylidene (H
2
SiSi) Transient (Angew. Chem. 5/2017). Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201612283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Tao Yang
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
| | - Beni B. Dangi
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
- Department of Chemistry Florida A&M University Tallahassee FL 32307 USA
| | - Ralf I. Kaiser
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
| | - Kang‐Heng Chao
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Bing‐Jian Sun
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Agnes H. H. Chang
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Thanh Lam Nguyen
- Department of Chemistry University of Texas at Austin Austin TX 78712 USA
| | - John F. Stanton
- Department of Chemistry University of Texas at Austin Austin TX 78712 USA
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Yang T, Dangi BB, Thomas AM, Kaiser RI, Sun BJ, Staś M, Chang AHH. Gas-Phase Synthesis of the Elusive Trisilicontetrahydride Species (Si 3H 4). J Phys Chem Lett 2017; 8:131-136. [PMID: 27959543 DOI: 10.1021/acs.jpclett.6b02710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The bimolecular gas-phase reaction of ground-state atomic silicon (Si; 3P) with disilane (Si2H6; 1A1g) was explored under single-collision conditions in a crossed molecular beam machine at a collision energy of 21 kJ mol-1. Combined with electronic structure calculations, the results suggest the formation of Si3H4 isomer(s) along with molecular hydrogen via indirect scattering dynamics through Si3H6 collision complex(es) and intersystem crossing from the triplet to the singlet surface. The nonadiabatic reaction dynamics can synthesize the energetically accessible singlet Si3H4 isomers in overall exoergic reaction(s) (-93 ± 21 kJ mol-1). All reasonable reaction products are either cyclic or hydrogen-bridged suggesting extensive isomerization processes from the reactants via the initially formed collision complex(es) to the fragmenting singlet intermediate(s). The underlying chemical dynamics of the silicon-disilane reaction are quite distinct from the isovalent carbon-ethane system that does not depict any reactivity at all, and open the door for an unconventional gas phase synthesis of hitherto elusive organosilicon molecules under single-collision conditions.
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Affiliation(s)
- Tao Yang
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | - Beni B Dangi
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | - Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | - Bing-Jian Sun
- Department of Chemistry, National Dong Hwa University , Shoufeng, Hualien 974, Taiwan
| | - Monika Staś
- Department of Physical Chemistry and Molecular Modeling, Opole University , 45-052 Opole, Poland
| | - Agnes H H Chang
- Department of Chemistry, National Dong Hwa University , Shoufeng, Hualien 974, Taiwan
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13
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Yang T, Dangi BB, Kaiser RI, Chao K, Sun B, Chang AHH, Nguyen TL, Stanton JF. Gas‐Phase Formation of the Disilavinylidene (H
2
SiSi) Transient. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611107] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Tao Yang
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
| | - Beni B. Dangi
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
- Department of Chemistry Florida A&M University Tallahassee FL 32307 USA
| | - Ralf I. Kaiser
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
| | - Kang‐Heng Chao
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Bing‐Jian Sun
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Agnes H. H. Chang
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Thanh Lam Nguyen
- Department of Chemistry University of Texas at Austin Austin TX 78712 USA
| | - John F. Stanton
- Department of Chemistry University of Texas at Austin Austin TX 78712 USA
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Yang T, Dangi BB, Kaiser RI, Chao K, Sun B, Chang AHH, Nguyen TL, Stanton JF. Gas‐Phase Formation of the Disilavinylidene (H
2
SiSi) Transient. Angew Chem Int Ed Engl 2017; 56:1264-1268. [DOI: 10.1002/anie.201611107] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Tao Yang
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
| | - Beni B. Dangi
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
- Department of Chemistry Florida A&M University Tallahassee FL 32307 USA
| | - Ralf I. Kaiser
- Department of Chemistry University of Hawai'i at Manoa Honolulu HI 96822 USA
| | - Kang‐Heng Chao
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Bing‐Jian Sun
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Agnes H. H. Chang
- Department of Chemistry National Dong Hwa University Shoufeng Hualien 974 Taiwan
| | - Thanh Lam Nguyen
- Department of Chemistry University of Texas at Austin Austin TX 78712 USA
| | - John F. Stanton
- Department of Chemistry University of Texas at Austin Austin TX 78712 USA
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Thomas AM, Yang T, Dangi BB, Kaiser RI, Kim GS, Mebel AM. Oxidation of the para-Tolyl Radical by Molecular Oxygen under Single-Collison Conditions: Formation of the para-Toloxy Radical. J Phys Chem Lett 2016; 7:5121-5127. [PMID: 27973866 DOI: 10.1021/acs.jpclett.6b02357] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Crossed molecular beam experiments were performed to elucidate the chemical dynamics of the para-tolyl (CH3C6H4) radical reaction with molecular oxygen (O2) at an average collision energy of 35.3 ± 1.4 kJ mol-1. Combined with theoretical calculations, the results show that para-tolyl is efficiently oxidized by molecular oxygen to para-toloxy (CH3C6H4O) plus ground-state atomic oxygen via a complex forming, overall exoergic reaction (experimental, -33 ± 16 kJ mol-1; computational, -42 ± 8 kJ mol-1). The reaction dynamics are analogous to those observed for the phenyl (C6H5) plus molecular oxygen system which suggests the methyl group is a spectator during para-tolyl oxidation and that application of phenyl thermochemistry and reaction rates to para-substituted aryls is likely a suitable approximation.
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Affiliation(s)
- Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Ma̅noa , Honolulu, Hawaii 96822, United States
| | - Tao Yang
- Department of Chemistry, University of Hawai'i at Ma̅noa , Honolulu, Hawaii 96822, United States
| | - Beni B Dangi
- Department of Chemistry, University of Hawai'i at Ma̅noa , Honolulu, Hawaii 96822, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Ma̅noa , Honolulu, Hawaii 96822, United States
| | - Gap-Sue Kim
- Dharma College, Dongguk University , 30, Pildong-ro 1-gil, Jung-gu, Seoul 04620, South Korea
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University , Miami, Florida 33199, United States
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Yang T, Thomas AM, Dangi BB, Kaiser RI, Wu MH, Sun BJ, Chang AHH. Formation of the 2,3-Dimethyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reaction of the Silylidyne Radical (SiH; X2Π) with Dimethylacetylene (CH3CCCH3; X1A1g). J Phys Chem A 2016; 120:7262-8. [DOI: 10.1021/acs.jpca.6b06995] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tao Yang
- Department
of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
| | - Aaron M. Thomas
- Department
of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
| | - Beni B. Dangi
- Department
of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
| | - Ralf I. Kaiser
- Department
of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States
| | - Mei-Hung Wu
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Bing-Jian Sun
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Agnes H. H. Chang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
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Yang T, Dangi BB, Kaiser RI, Bertels LW, Head-Gordon M. A Combined Experimental and Theoretical Study on the Formation of the 2-Methyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reactions of the Silylidyne Radical (SiH; X(2)Π) with Methylacetylene (CH3CCH; X(1)A1) and D4-Methylacetylene (CD3CCD; X(1)A1). J Phys Chem A 2016; 120:4872-83. [PMID: 26837568 DOI: 10.1021/acs.jpca.5b12457] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The bimolecular gas-phase reactions of the ground-state silylidyne radical (SiH; X(2)Π) with methylacetylene (CH3CCH; X(1)A1) and D4-methylacetylene (CD3CCD; X(1)A1) were explored at collision energies of 30 kJ mol(-1) under single-collision conditions exploiting the crossed molecular beam technique and complemented by electronic structure calculations. These studies reveal that the reactions follow indirect scattering dynamics, have no entrance barriers, and are initiated by the addition of the silylidyne radical to the carbon-carbon triple bond of the methylacetylene molecule either to one carbon atom (C1; [i1]/[i2]) or to both carbon atoms concurrently (C1-C2; [i3]). The collision complexes [i1]/[i2] eventually isomerize via ring-closure to the c-SiC3H5 doublet radical intermediate [i3], which is identified as the decomposing reaction intermediate. The hydrogen atom is emitted almost perpendicularly to the rotational plane of the fragmenting complex resulting in a sideways scattering dynamics with the reaction being overall exoergic by -12 ± 11 kJ mol(-1) (experimental) and -1 ± 3 kJ mol(-1) (computational) to form the cyclic 2-methyl-1-silacycloprop-2-enylidene molecule (c-SiC3H4; p1). In line with computational data, experiments of silylidyne with D4-methylacetylene (CD3CCD; X(1)A1) depict that the hydrogen is emitted solely from the silylidyne moiety but not from methylacetylene. The dynamics are compared to those of the related D1-silylidyne (SiD; X(2)Π)-acetylene (HCCH; X(1)Σg(+)) reaction studied previously in our group, and from there, we discovered that the methyl group acts primarily as a spectator in the title reaction. The formation of 2-methyl-1-silacycloprop-2-enylidene under single-collision conditions via a bimolecular gas-phase reaction augments our knowledge of the hitherto poorly understood silylidyne (SiH; X(2)Π) radical reactions with small hydrocarbon molecules leading to the synthesis of organosilicon molecules in cold molecular clouds and in carbon-rich circumstellar envelopes.
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Affiliation(s)
- Tao Yang
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | - Beni B Dangi
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | - Luke W Bertels
- Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - Martin Head-Gordon
- Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
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Yang T, Dangi BB, Thomas AM, Sun BJ, Chou TJ, Chang AHH, Kaiser RI. Gas-Phase Synthesis of 1-Silacyclopenta-2,4-diene. Angew Chem Int Ed Engl 2016; 55:7983-7. [PMID: 27219669 DOI: 10.1002/anie.201602064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/09/2016] [Indexed: 11/08/2022]
Abstract
Silole (1-silacyclopenta-2,4-diene) was synthesized for the first time by the bimolecular reaction of the simplest silicon-bearing radical, silylidyne (SiH), with 1,3-butadiene (C4 H6 ) in the gas phase under single-collision conditions. The absence of consecutive collisions of the primary reaction product prevents successive reactions of the silole by Diels-Alder dimerization, thus enabling the clean gas-phase synthesis of this hitherto elusive cyclic species from acyclic precursors in a single-collision event. Our method opens up a versatile and unconventional path to access a previously rather obscure class of organosilicon molecules (substituted siloles), which have been difficult to access through classical synthetic methods.
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Affiliation(s)
- Tao Yang
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI, 96822, USA
| | - Beni B Dangi
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI, 96822, USA
| | - Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI, 96822, USA
| | - Bing-Jian Sun
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien, 974, Taiwan
| | - Tzu-Jung Chou
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien, 974, Taiwan
| | - Agnes H H Chang
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien, 974, Taiwan.
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI, 96822, USA.
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19
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Yang T, Dangi BB, Thomas AM, Kaiser RI. Untangling the reaction dynamics of the silylidyne radical (SiH; X2Π) with acetylene (C2H2; X1Σg+). Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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Affiliation(s)
- Tao Yang
- Department of Chemistry; University of Hawai'i at Manoa; Honolulu HI 96822 USA
| | - Beni B. Dangi
- Department of Chemistry; University of Hawai'i at Manoa; Honolulu HI 96822 USA
| | - Aaron M. Thomas
- Department of Chemistry; University of Hawai'i at Manoa; Honolulu HI 96822 USA
| | - Bing-Jian Sun
- Department of Chemistry; National Dong Hwa University; Shoufeng Hualien 974 Taiwan
| | - Tzu-Jung Chou
- Department of Chemistry; National Dong Hwa University; Shoufeng Hualien 974 Taiwan
| | - Agnes H. H. Chang
- Department of Chemistry; National Dong Hwa University; Shoufeng Hualien 974 Taiwan
| | - Ralf I. Kaiser
- Department of Chemistry; University of Hawai'i at Manoa; Honolulu HI 96822 USA
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21
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Yang T, Dangi BB, Maksyutenko P, Kaiser RI, Bertels LW, Head-Gordon M. Combined Experimental and Theoretical Study on the Formation of the Elusive 2-Methyl-1-silacycloprop-2-enylidene Molecule under Single Collision Conditions via Reactions of the Silylidyne Radical (SiH; X(2)Π) with Allene (H2CCCH2; X(1)A1) and D4-Allene (D2CCCD2; X(1)A1). J Phys Chem A 2015; 119:12562-78. [PMID: 26535955 DOI: 10.1021/acs.jpca.5b09773] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The crossed molecular beam reactions of the ground-state silylidyne radical (SiH; X(2)Π) with allene (H2CCCH2; X(1)A1) and D4-allene (D2CCCD2; X(1)A1) were carried out at collision energies of 30 kJ mol(-1). Electronic structure calculations propose that the reaction of silylidyne with allene has no entrance barrier and is initiated by silylidyne addition to the π electron density of allene either to one carbon atom (C1/C2) or to both carbon atoms simultaneously via indirect (complex forming) reaction dynamics. The initially formed addition complexes isomerize via two distinct reaction pathways, both leading eventually to a cyclic SiC3H5 intermediate. The latter decomposes through a loose exit transition state via an atomic hydrogen loss perpendicularly to the plane of the decomposing complex (sideways scattering) in an overall exoergic reaction (experimentally: -19 ± 13 kJ mol(-1); computationally: -5 ± 3 kJ mol(-1)). This hydrogen loss yields the hitherto elusive 2-methyl-1-silacycloprop-2-enylidene molecule (c-SiC3H4), which can be derived from the closed-shell cyclopropenylidene molecule (c-C3H2) by replacing a hydrogen atom with a methyl group and the carbene carbon atom by the isovalent silicon atom. The synthesis of the 2-methyl-1-silacycloprop-2-enylidene molecule in the bimolecular gas-phase reaction of silylidyne with allene enriches our understanding toward the formation of organosilicon species in the gas phase of the interstellar medium in particular via exoergic reactions of no entrance barrier. This facile route to 2-methyl-1-silacycloprop-2-enylidene via a silylidyne radical reaction with allene opens up a versatile approach to form hitherto poorly characterized silicon-bearing species in extraterrestrial environments; this reaction class might represent the missing link, leading from silicon-bearing radicals via organosilicon chemistry eventually to silicon-carbon-rich interstellar grains even in cold molecular clouds where temperatures are as low as 10 K.
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Affiliation(s)
- Tao Yang
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States.,Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - Beni B Dangi
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States.,Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - Pavlo Maksyutenko
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States.,Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States.,Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - Luke W Bertels
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States.,Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
| | - Martin Head-Gordon
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States.,Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States
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Parker DSN, Yang T, Dangi BB, Kaiser RI, Bera PP, Lee TJ. LOW TEMPERATURE FORMATION OF NITROGEN-SUBSTITUTED POLYCYCLIC AROMATIC HYDROCARBONS (PANHs)—BARRIERLESS ROUTES TO DIHYDRO(iso)QUINOLINES. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/0004-637x/815/2/115] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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23
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Maity S, Dangi BB, Parker DSN, Kaiser RI, Lin HM, E HP, Sun BJ, Chang AHH. Combined crossed molecular beam and ab initio investigation of the reaction of boron monoxide (BO; X(2)Σ(+)) with 1,3-butadiene (CH2CHCHCH2; X(1)Ag) and its deuterated counterparts. J Phys Chem A 2015; 119:1094-107. [PMID: 25626151 DOI: 10.1021/jp511715e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reactions of the boron monoxide ((11)BO; X(2)Σ(+)) radical with 1,3-butadiene (CH2CHCHCH2; X(1)Ag) and its partially deuterated counterparts, 1,3-butadiene-d2 (CH2CDCDCH2; X(1)Ag) and 1,3-butadiene-d4 (CD2CHCHCD2; X(1)Ag), were investigated under single collision conditions exploiting a crossed molecular beams machine. The experimental data were combined with the state-of-the-art ab initio electronic structure calculations and statistical RRKM calculations to investigate the underlying chemical reaction dynamics and reaction mechanisms computationally. Our investigations revealed that the reaction followed indirect scattering dynamics through the formation of (11)BOC4H6 doublet radical intermediates via the barrierless addition of the (11)BO radical to the terminal carbon atom (C1/C4) and/or the central carbon atom (C2/C3) of 1,3-butadiene. The resulting long-lived (11)BOC4H6 intermediate(s) underwent isomerization and/or unimolecular decomposition involving eventually at least two distinct atomic hydrogen loss pathways to 1,3-butadienyl-1-oxoboranes (CH2CHCHCH(11)BO) and 1,3-butadienyl-2-oxoboranes (CH2C ((11)BO)CHCH2) in overall exoergic reactions via tight exit transition states. Utilizing partially deuterated 1,3-butadiene-d2 and -d4, we revealed that the hydrogen loss from the methylene moiety (CH2) dominated with 70 ± 10% compared to an atomic hydrogen loss from the methylidyne group (CH) of only 30 ± 10%; these data agree nicely with the theoretically predicted branching ratio of 80% versus 19%.
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Affiliation(s)
- Surajit Maity
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
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24
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Yang T, Parker DSN, Dangi BB, Kaiser RI, Mebel AM. Formation of 5- and 6-methyl-1H-indene (C10H10) via the reactions of the para-tolyl radical (C6H4CH3) with allene (H2CCCH2) and methylacetylene (HCCCH3) under single collision conditions. Phys Chem Chem Phys 2015; 17:10510-9. [DOI: 10.1039/c4cp04288c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Flux contour map for the reactions of the p-tolyl radical with allene-d4 and methylacetylene-d4 at collision energies of around 48 kJ mol−1.
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Affiliation(s)
- Tao Yang
- Department of Chemistry
- University of Hawaii at Manoa
- Honolulu
- USA
| | | | - Beni B. Dangi
- Department of Chemistry
- University of Hawaii at Manoa
- Honolulu
- USA
| | - Ralf I. Kaiser
- Department of Chemistry
- University of Hawaii at Manoa
- Honolulu
- USA
| | - Alexander M. Mebel
- Department of Chemistry and Biochemistry
- Florida International University
- Miami
- USA
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25
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Parker DSN, Dangi BB, Kaiser RI, Jamal A, Ryazantsev M, Morokuma K. Formation of 6-methyl-1,4-dihydronaphthalene in the reaction of the p-tolyl radical with 1,3-butadiene under single-collision conditions. J Phys Chem A 2014; 118:12111-9. [PMID: 25407848 DOI: 10.1021/jp509990u] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Crossed molecular beam reactions of p-tolyl (C7H7) plus 1,3-butadiene (C4H6), p-tolyl (C7H7) plus 1,3-butadiene-d6 (C4D6), and p-tolyl-d7 (C7D7) plus 1,3-butadiene (C4H6) were carried out under single-collision conditions at collision energies of about 55 kJ mol(-1). 6-Methyl-1,4-dihydronaphthalene was identified as the major reaction product formed at fractions of about 94% with the monocyclic isomer (trans-1-p-tolyl-1,3-butadiene) contributing only about 6%. The reaction is initiated by barrierless addition of the p-tolyl radical to the terminal carbon atom of the 1,3-butadiene via a van der Waals complex. The collision complex isomerizes via cyclization to a bicyclic intermediate, which then ejects a hydrogen atom from the bridging carbon to form 6-methyl-1,4-dihydronaphthalene through a tight exit transition state located about 27 kJ mol(-1) above the separated products. This is the dominant channel under the present experimental conditions. Alternatively, the collision complex can also undergo hydrogen ejection to form trans-1-p-tolyl-1,3-butadiene; this is a minor contributor to the present experiment. The de facto barrierless formation of a methyl-substituted aromatic hydrocarbons by dehydrogenation via a single event represents an important step in the formation of polycyclic aromatic hydrocarbons (PAHs) and their partially hydrogenated analogues in combustion flames and the interstellar medium.
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Affiliation(s)
- Dorian S N Parker
- Department of Chemistry, University of Hawaii at Manoa , Honolulu, Hawaii 96822, United States
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26
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Maity S, Dangi BB, Parker DSN, Kaiser RI, An Y, Sun BJ, Chang AHH. Combined crossed molecular beam and ab initio investigation of the multichannel reaction of boron monoxide (BO; X2Σ+) with Propylene (CH3CHCH2; X1A'): competing atomic hydrogen and methyl loss pathways. J Phys Chem A 2014; 118:9632-45. [PMID: 25238644 DOI: 10.1021/jp507001r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The reaction dynamics of boron monoxide ((11)BO; X(2)Σ(+)) with propylene (CH(3)CHCH(2); X(1)A') were investigated under single collision conditions at a collision energy of 22.5 ± 1.3 kJ mol(-1). The crossed molecular beam investigation combined with ab initio electronic structure and statistical (RRKM) calculations reveals that the reaction follows indirect scattering dynamics and proceeds via the barrierless addition of boron monoxide radical with its radical center located at the boron atom. This addition takes place to either the terminal carbon atom (C1) and/or the central carbon atom (C2) of propylene reactant forming (11)BOC(3)H(6) intermediate(s). The long-lived (11)BOC(3)H(6) doublet intermediate(s) underwent unimolecular decomposition involving at least three competing reaction mechanisms via an atomic hydrogen loss from the vinyl group, an atomic hydrogen loss from the methyl group, and a methyl group elimination to form cis-/trans-1-propenyl-oxo-borane (CH(3)CHCH(11)BO), 3-propenyl-oxo-borane (CH(2)CHCH(2)(11)BO), and ethenyl-oxo-borane (CH(2)CH(11)BO), respectively. Utilizing partially deuterated propylene (CD(3)CHCH(2) and CH(3)CDCD(2)), we reveal that the loss of a vinyl hydrogen atom is the dominant hydrogen elimination pathway (85 ± 10%) forming cis-/trans-1-propenyl-oxo-borane, compared to the loss of a methyl hydrogen atom (15 ± 10%) leading to 3-propenyl-oxo-borane. The branching ratios for an atomic hydrogen loss from the vinyl group, an atomic hydrogen loss from the methyl group, and a methyl group loss are experimentally derived to be 26 ± 8%:5 ± 3%:69 ± 15%, respectively; these data correlate nicely with the branching ratios calculated via RRKM theory of 19%:5%:75%, respectively.
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Affiliation(s)
- Surajit Maity
- Department of Chemistry, University of Hawaii at Manoa , Honolulu, Hawaii 96822, United States
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27
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Yang T, Dangi BB, Parker DSN, Kaiser RI, An Y, Chang AHH. A combined crossed molecular beams and ab initio investigation on the formation of vinylsulfidoboron (C₂H₃¹¹B³²S). Phys Chem Chem Phys 2014; 16:17580-7. [PMID: 25026168 DOI: 10.1039/c4cp01651c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We exploited crossed molecular beams techniques and electronic structure calculations to provide compelling evidence that the vinylsulfidoboron molecule (C2H3(11)B(32)S) - the simplest member of hitherto elusive olefinic organo-sulfidoboron molecules (RBS) - can be formed via the gas phase reaction of boron monosulfide ((11)B(32)S) with ethylene (C2H4) under single collision conditions. The reaction mechanism follows indirect scattering dynamics via a barrierless addition of the boron monosulfide radical to the carbon-carbon double bond of ethylene. The initial reaction complex can either decompose to vinylsulfidoboron (C2H3(11)B(32)S) via the emission of a hydrogen atom from the sp(3) hybridized carbon atom, or isomerize via a 1,2-hydrogen shift prior to a hydrogen loss from the terminal carbon atom to form vinylsulfidoboron. Statistical (RRKM) calculations predict branching ratios of 8% and 92% for both pathways leading to vinylsulfidoboron, respectively. A comparison between the boron monosulfide ((11)B(32)S) plus ethylene and the boron monoxide ((11)BO) plus ethylene systems indicates that both reactions follow similar reaction mechanisms involving addition - elimination and addition - hydrogen migration - elimination pathways. Our experimental findings open up a novel pathway to access the previously poorly-characterized class of organo-sulfidoboron molecules via bimolecular gas phase reactions, which are difficult to form through 'classical' organic synthesis.
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Affiliation(s)
- Tao Yang
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA.
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Kaiser RI, Dangi BB, Yang T, Parker DSN, Mebel AM. Reaction dynamics of the 4-methylphenyl radical (p-tolyl) with 1,2-butadiene (1-methylallene): are methyl groups purely spectators? J Phys Chem A 2014; 118:6181-90. [PMID: 25084134 DOI: 10.1021/jp505868q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reactions of the 4-tolyl radical (C6H4CH3) and of the D7-4-tolyl radical (C6D4CD3) with 1,2-butadiene (C4H6) have been probed in crossed molecular beams under single collision conditions at a collision energy of about 54 kJ mol(-1) and studied theoretically using ab initio G3(MP2,CC)//B3LYP/6-311G** and statistical RRKM calculations. The results show that the reaction proceeds via indirect scattering dynamics through the formation of a van-der-Waals complex followed by the addition of the radical center of the 4-tolyl radical to the C1 or C3 carbon atoms of 1,2-butadiene. The collision complexes then isomerize by migration of the tolyl group from the C1 (C3) to the C2 carbon atom of the 1,2-butadiene moiety. The resulting intermediate undergoes unimolecular decomposition via elimination of a hydrogen atom from the methyl group of the 1,2-butadiene moiety through a rather loose exit transition state leading to 2-para-tolyl-1,3-butadiene (p4), which likely presents the major reaction product. Our observation combined with theoretical calculations suggest that one methyl group (at the phenyl group) acts as a spectator in the reaction, whereas the other one (at the allene moiety) is actively engaged in the underlying chemical dynamics. On the contrary to the reaction of the phenyl radical with allene, which leads to the formation of indene, the substitution of a hydrogen atom by a methyl group in allene essentially eliminates the formation of bicyclic PAHs such as substituted indenes in the 4-tolyl plus 1,2-butadiene reaction.
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Affiliation(s)
- Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
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Yang T, Parker DSN, Dangi BB, Kaiser RI, Kislov VV, Mebel AM. Crossed Beam Reactions of the Phenyl (C6H5; X2A1) and Phenyl-d5 Radical (C6D5; X2A1) with 1,2-Butadiene (H2CCCHCH3; X1A′). J Phys Chem A 2014; 118:4372-81. [DOI: 10.1021/jp411642w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tao Yang
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Dorian S. N. Parker
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Beni B. Dangi
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Ralf I. Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Vadim V. Kislov
- Department of Chemistry and
Biochemistry, Florida International University, Miami, Florida 33174, United States
| | - Alexander M. Mebel
- Department of Chemistry and
Biochemistry, Florida International University, Miami, Florida 33174, United States
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Yang T, Parker DSN, Dangi BB, Kaiser RI, Stranges D, Su YH, Chen SY, Chang AHH, Mebel AM. Directed Gas-Phase Formation of the Ethynylsulfidoboron Molecule. J Am Chem Soc 2014; 136:8387-92. [DOI: 10.1021/ja502636u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tao Yang
- Department
of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Dorian S. N. Parker
- Department
of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Beni B. Dangi
- Department
of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Ralf I. Kaiser
- Department
of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Domenico Stranges
- Department
of Chemistry, Sapienza University of Rome, Rome 00185, Italy
| | - Yuan-Hsiang Su
- Department
of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Si-Ying Chen
- Department
of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Agnes H. H. Chang
- Department
of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan
| | - Alexander M. Mebel
- Department
of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
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Dangi BB, Parker DSN, Yang T, Kaiser RI, Mebel AM. Gas-Phase Synthesis of the Benzyl Radical (C 6H 5CH 2). Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201310612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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32
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Parker DSN, Dangi BB, Kaiser RI, Jamal A, Ryazantsev MN, Morokuma K, Korte A, Sander W. An Experimental and Theoretical Study on the Formation of 2-Methylnaphthalene (C11H10/C11H3D7) in the Reactions of the Para-Tolyl (C7H7) and Para-Tolyl-d7 (C7D7) with Vinylacetylene (C4H4). J Phys Chem A 2014; 118:2709-18. [DOI: 10.1021/jp501210d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dorian S. N. Parker
- Department
of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Beni B. Dangi
- Department
of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Ralf I. Kaiser
- Department
of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Adeel Jamal
- Department
of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - Mikhail N. Ryazantsev
- Department
of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
- St. Petersburg Academic University Nanotechnology Research and Education Center RAS, St. Petersburg, Russia
| | - Keiji Morokuma
- Department
of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
- Fukui
Institute for Fundamental Chemistry, Kyoto University, Sakyo, Kyoto 606-8103, Japan
| | - André Korte
- Faculty
of Chemistry and Biochemistry, Ruhr Universität Bochum, Universitätsstraße
150, 44801 Bochum, Germany
| | - Wolfram Sander
- Faculty
of Chemistry and Biochemistry, Ruhr Universität Bochum, Universitätsstraße
150, 44801 Bochum, Germany
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Dangi BB, Parker DSN, Yang T, Kaiser RI, Mebel AM. Gas-Phase Synthesis of the Benzyl Radical (C6H5CH2). Angew Chem Int Ed Engl 2014; 53:4608-13. [DOI: 10.1002/anie.201310612] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/25/2014] [Indexed: 11/10/2022]
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34
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Dangi BB, Yang T, Kaiser RI, Mebel AM. Reaction dynamics of the 4-methylphenyl radical (C6H4CH3; p-tolyl) with isoprene (C5H8) – formation of dimethyldihydronaphthalenes. Phys Chem Chem Phys 2014; 16:16805-14. [DOI: 10.1039/c4cp01056f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction dynamics and energetics of 4-methylphenyl radical with isoprene are reported under single collision condition at collision energy of 58 kJ mol−1 by exploiting the crossed molecular beam technique and electronic structure calculations.
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Affiliation(s)
- Beni B. Dangi
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - Tao Yang
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - Ralf I. Kaiser
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - Alexander M. Mebel
- Department of Chemistry and Biochemistry
- Florida International University
- Miami, USA
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Parker DSN, Maity S, Dangi BB, Kaiser RI, Landera A, Mebel AM. Understanding the chemical dynamics of the reactions of dicarbon with 1-butyne, 2-butyne, and 1,2-butadiene – toward the formation of resonantly stabilized free radicals. Phys Chem Chem Phys 2014; 16:12150-63. [DOI: 10.1039/c4cp00639a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Experimental and electronic structure investigation of the reactions of dicarbon with C4H6 isomers and their isomer specific reaction routes.
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Affiliation(s)
| | - Surajit Maity
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - Beni B. Dangi
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - Ralf I. Kaiser
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - Alexander Landera
- Department of Chemistry & Biochemistry
- Florida International University
- Miami, USA
| | - Alexander M. Mebel
- Department of Chemistry & Biochemistry
- Florida International University
- Miami, USA
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36
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Kaiser RI, Maity S, Dangi BB, Su YS, Sun BJ, Chang AHH. A crossed molecular beam and ab initio investigation of the exclusive methyl loss pathway in the gas phase reaction of boron monoxide (BO; X2Σ+) with dimethylacetylene (CH3CCCH3; X1A1g). Phys Chem Chem Phys 2014; 16:989-97. [DOI: 10.1039/c3cp53930j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Parker DSN, Dangi BB, Balucani N, Stranges D, Mebel AM, Kaiser RI. Gas-phase synthesis of phenyl oxoborane (C6H5BO) via the reaction of boron monoxide with benzene. J Org Chem 2013; 78:11896-900. [PMID: 24191702 DOI: 10.1021/jo401942z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Organyl oxoboranes (RBO) are valuable reagents in organic synthesis due to their role in Suzuki coupling reactions. However, organyl oxoboranes (RBO) are only found in trimeric forms (RBO3) commonly known as boronic acids or boroxins; obtaining their monomers has proved a complex endeavor. Here, we demonstrate an oligomerization-free formation of organyl oxoborane (RBO) monomers in the gas phase by a radical substitution reaction under single-collision conditions in the gas phase. Using the cross molecular beams technique, phenyl oxoborane (C6H5BO) is formed through the reaction of boronyl radicals (BO) with benzene (C6H6). The reaction is indirect, initially forming a van der Waals complex that isomerizes below the energy of the reactants and eventually forming phenyl oxoborane by hydrogen emission in an overall exoergic radical-hydrogen atom exchange mechanism.
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Affiliation(s)
- Dorian S N Parker
- Department of Chemistry, University of Hawaii at Manoa , 2545 The Mall, Honolulu, Hawaii 96822-2275, United States
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38
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Maity S, Parker DSN, Dangi BB, Kaiser RI, Fau S, Perera A, Bartlett RJ. A crossed molecular beam and ab-initio investigation of the reaction of boron monoxide (BO; X2Σ+) with methylacetylene (CH3CCH; X1A1): competing atomic hydrogen and methyl loss pathways. J Phys Chem A 2013; 117:11794-807. [PMID: 23651442 DOI: 10.1021/jp402743y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The gas-phase reaction of boron monoxide ((11)BO; X(2)Σ(+)) with methylacetylene (CH3CCH; X(1)A1) was investigated experimentally using crossed molecular beam technique at a collision energy of 22.7 kJ mol(-1) and theoretically using state of the art electronic structure calculation, for the first time. The scattering dynamics were found to be indirect (complex forming reaction) and the reaction proceeded through the barrier-less formation of a van-der-Waals complex ((11)BOC3H4) followed by isomerization via the addition of (11)BO(X(2)Σ(+)) to the C1 and/or C2 carbon atom of methylacetylene through submerged barriers. The resulting (11)BOC3H4 doublet radical intermediates underwent unimolecular decomposition involving three competing reaction mechanisms via two distinct atomic hydrogen losses and a methyl group elimination. Utilizing partially deuterated methylacetylene reactants (CD3CCH; CH3CCD), we revealed that the initial addition of (11)BO(X(2)Σ(+)) to the C1 carbon atom of methylacetylene was followed by hydrogen loss from the acetylenic carbon atom (C1) and from the methyl group (C3) leading to 1-propynyl boron monoxide (CH3CC(11)BO) and propadienyl boron monoxide (CH2CCH(11)BO), respectively. Addition of (11)BO(X(2)Σ(+)) to the C1 of methylacetylene followed by the migration of the boronyl group to the C2 carbon atom and/or an initial addition of (11)BO(X(2)Σ(+)) to the sterically less accessible C2 carbon atom of methylacetylene was followed by loss of a methyl group leading to the ethynyl boron monoxide product (HCC(11)BO) in an overall exoergic reaction (78 ± 23 kJ mol(-1)). The branching ratios of these channels forming CH2CCH(11)BO, CH3CC(11)BO, and HCC(11)BO were derived to be 4 ± 3%, 40 ± 5%, and 56 ± 15%, respectively; these data are in excellent agreement with the calculated branching ratios using statistical RRKM theory yielding 1%, 38%, and 61%, respectively.
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Affiliation(s)
- Surajit Maity
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
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Dangi BB, Maity S, Kaiser RI, Mebel AM. A Combined Crossed Beam and Ab Initio Investigation of the Gas Phase Reaction of Dicarbon Molecules (C2; X1Σg+/a3Πu) with Propene (C3H6; X1A′): Identification of the Resonantly Stabilized Free Radicals 1- and 3-Vinylpropargyl. J Phys Chem A 2013; 117:11783-93. [DOI: 10.1021/jp402700j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Beni B. Dangi
- Department of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United
States
| | - Surajit Maity
- Department of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United
States
| | - Ralf I. Kaiser
- Department of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United
States
| | - Alexander M. Mebel
- Department of Chemistry
and Biochemistry, Florida International University, Miami, Florida 33199, United States
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Dangi BB, Parker DSN, Kaiser RI, Jamal A, Mebel AM. A Combined Experimental and Theoretical Study on the Gas-Phase Synthesis of Toluene under Single Collision Conditions. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201302344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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41
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Dangi BB, Parker DSN, Kaiser RI, Jamal A, Mebel AM. A Combined Experimental and Theoretical Study on the Gas-Phase Synthesis of Toluene under Single Collision Conditions. Angew Chem Int Ed Engl 2013; 52:7186-9. [DOI: 10.1002/anie.201302344] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Indexed: 11/05/2022]
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Dangi BB, Ervin KM. Optimization of a quadrupole ion storage trap as a source for time-of-flight mass spectrometry. J Mass Spectrom 2012; 47:41-48. [PMID: 22282088 DOI: 10.1002/jms.2024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Designs of a quadrupole ion trap (QIT) as a source for time-of-flight (TOF) mass spectrometry are evaluated for mass resolution, ion trapping, and laser activation of trapped ions. Comparisons are made with the standard hyperbolic electrode ion trap geometry for TOF mass analysis in both linear and reflectron modes. A parallel-plate design for the QIT is found to give significantly improved TOF mass spectrometer performance. Effects of ion temperature, trapped ion cloud size, mass, and extraction field on mass resolution are investigated in detail by simulation of the TOF peak profiles. Mass resolution (m/Δm) values of several thousand are predicted even at room temperature with moderate extraction fields for the optimized design. The optimized design also allows larger radial ion collection size compared with the hyperbolic ion trap, without compromising the mass resolution. The proposed design of the QIT also improves the ion-laser interaction volume and photon collection efficiency for fluorescence measurements on trapped ions.
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Affiliation(s)
- Beni B Dangi
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St. MS 216, Reno, NV 89557-0216, USA
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Dangi BB, Sassin NA, Ervin KM. Pulsed ion extraction diagnostics in a quadrupole ion trap linear time-of-flight mass spectrometer. Rev Sci Instrum 2010; 81:063302. [PMID: 20590232 DOI: 10.1063/1.3436659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Pulsed extraction techniques are investigated for a quadrupole ion trap (QIT) interfaced to a linear time-of-flight (TOF) mass analyzer. A nonfocusing short-pulse mode of operation is developed and characterized. The short-pulse mode creates a near-monoenergetic ion packet, which is useful for reaction kinetics experiments and for making diagnostic measurements of the ion cloud size in the trap. Monopolar and bipolar pulsing modes, with the voltage pulses applied to one or both QIT endcaps to extract the ions into the TOF region, are compared. Ion TOF peak distributions are characterized experimentally and by ion trajectory simulations. Also, first-order spatial (Wiley-McLaren) focusing of ions is characterized for the conventional long-pulse extraction mode. The nonparallel fields in the QIT, which serves as the first acceleration region in the linear-TOF mass spectrometer, are shown to degrade spatial focusing and mass resolution.
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Affiliation(s)
- Beni B Dangi
- Department of Chemistry and Chemical Physics Program, University of Nevada, Reno, 1664 N. Virginia St., MS 216, Reno, Nevada 89557-0216, USA
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Sassin NA, Everhart SC, Dangi BB, Ervin KM, Cline JI. Fluorescence and photodissociation of rhodamine 575 cations in a quadrupole ion trap. J Am Soc Mass Spectrom 2009; 20:96-104. [PMID: 18849170 DOI: 10.1016/j.jasms.2008.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 09/05/2008] [Accepted: 09/05/2008] [Indexed: 05/26/2023]
Abstract
The fluorescence and photodissociation of rhodamine 575 cations confined to a quadrupole ion trap are observed during laser irradiation at 488 nm. The kinetics of photodissociation is measured by time-dependent mass spectra and time-dependent fluorescence. The rhodamine ion signal and fluorescence decay are studied as functions of buffer gas pressure, laser fluence, and irradiation time. The decay rates of the ions in the mass spectra agree with decay rates of the fluorescence. Some of the fragment ions also fluoresce and further dissociate. The photodissociation rate is found to depend on the incident laser fluence and buffer gas pressure. The implications of rapid absorption/fluorescence cycling for photodissociation of dye-labeled biomolecular ions under continuous irradiation are discussed.
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Affiliation(s)
- Nicholas A Sassin
- Department of Chemistry and Chemical Physics Program, University of Nevada, Reno, Reno, Nevada, USA
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