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Li H, Suits AG. Universal crossed beam imaging studies of polyatomic reaction dynamics. Phys Chem Chem Phys 2020; 22:11126-11138. [DOI: 10.1039/d0cp00522c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Crossed-beam imaging studies of polyatomic reactions show surprising dynamics not anticipated by extrapolation from smaller model systems.
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Affiliation(s)
- Hongwei Li
- Department of Chemistry
- University of Missouri
- Columbia
- USA
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2
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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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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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] [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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Thorwirth S, Kaiser RI, Crabtree KN, McCarthy MC. Spectroscopic and structural characterization of three silaisocyanides: exploring an elusive class of reactive molecules at high resolution. Chem Commun (Camb) 2015; 51:11305-8. [PMID: 26083592 DOI: 10.1039/c5cc02548f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Silaisocyanoacetylene, HCCNSi, silaisocyanodiacetylene, HC4NSi, and silaisocyanogen, NCNSi, have been identified spectroscopically for the first time. All three transient species were observed at high spectral resolution at centimeter wavelengths (5-40 GHz) by microwave spectroscopy. From detection of less abundant isotopic species and high-level quantum-chemical calculations, accurate empirical equilibrium structures have been derived for HCCNSi and NCNSi. All three molecules are promising candidates for future radio astronomical detection owing in part to large calculated dipole moments.
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Affiliation(s)
- Sven Thorwirth
- I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany.
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Parker DSN, Mebel AM, Kaiser RI. The role of isovalency in the reactions of the cyano (CN), boron monoxide (BO), silicon nitride (SiN), and ethynyl (C2H) radicals with unsaturated hydrocarbons acetylene (C2H2) and ethylene (C2H4). Chem Soc Rev 2014; 43:2701-13. [DOI: 10.1039/c3cs60328h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The classification of chemical reactions based on shared characteristics is at the heart of the chemical sciences, and is well exemplified by Langmuir's concept of isovalency, in which ‘two molecular entities with the same number of valence electrons have similar chemistries’.
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Affiliation(s)
- D. S. N. Parker
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
| | - A. M. Mebel
- Department of Chemistry and Biochemistry
- Florida International University
- Miami, USA
| | - R. I. Kaiser
- Department of Chemistry
- University of Hawai'i at Manoa
- Honolulu, USA
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Affiliation(s)
- Annette D. Allen
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Thomas T. Tidwell
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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