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Williams PE, Jankiewicz BJ, Yang L, Kenttämaa HI. Properties and reactivity of gaseous distonic radical ions with aryl radical sites. Chem Rev 2013; 113:6949-85. [PMID: 23987564 PMCID: PMC3889672 DOI: 10.1021/cr400121w] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Peggy E. Williams
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906
| | | | - Linan Yang
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906
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Li X, Paldus J. Force field of para- and metabenzyne diradicals: A multireference coupled-cluster study. J Chem Phys 2010; 132:114103. [DOI: 10.1063/1.3354947] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Wei H, Hrovat DA, Mo Y, Hoffmann R, Borden WT. The Contributions of Through-Bond Interactions to the Singlet−Triplet Energy Difference in 1,3-Dehydrobenzene. J Phys Chem A 2009; 113:10351-8. [DOI: 10.1021/jp905222f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Haiyan Wei
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5070, Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, and Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301
| | - David A. Hrovat
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5070, Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, and Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301
| | - Yirong Mo
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5070, Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, and Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301
| | - Roald Hoffmann
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5070, Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, and Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301
| | - Weston Thatcher Borden
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5070, Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, and Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301
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Venkataramani S, Winkler M, Sander W. Trifluoro-1,3,5-tridehydrobenzene. Angew Chem Int Ed Engl 2007; 46:4888-93. [PMID: 17568464 DOI: 10.1002/anie.200700536] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Sugumar Venkataramani
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
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Winkler M, Cakir B, Sander W. 3,5-PyridyneA Heterocyclic meta-Benzyne Derivative. J Am Chem Soc 2004; 126:6135-49. [PMID: 15137779 DOI: 10.1021/ja039142u] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
3,5-Pyridyne (3) has been generated by flash vacuum pyrolysis of 3,5-diiodopyridine (20) and 3,5-dinitropyridine (21) and characterized by IR spectroscopy in cryogenic argon matrices. The aryne can clearly be distinguished from other side products by its photolability at 254 nm, inducing a rapid ring-opening presumably to (Z)-1-aza-hex-3-ene-1,5-diyne. As byproducts of the pyrolysis, HCN and butadiyne were identified, together with traces of acetylene, cyanoacetylene, (E)-1-aza-hex-3-ene-1,5-diyne, and the 3-iodo-5-pyridyl radical (from 20). Several pathways for rearrangements and fragmentations of 3 and of the parent meta-benzyne (1) have been explored computationally by density functional theory and ab initio quantum chemical methods. The lowest energy decomposition pathway of biradicals 1 and 3 is a ring-opening process accompanied by hydrogen migration, leading to (Z)-hex-3-ene-1,5-diyne [(Z)-10] and (Z)-3-aza-hex-3-ene-1,5-diyne [(Z)-24], respectively. Both reactions require activation energies of 45-50 kcal mol(-1). Mechanisms leading from (Z)-24 or directly from 3 to the experimentally observed byproducts are discussed. Upon replacement of the C(5)H moiety by N in meta-benzyne, high-level calculations predict a modest shortening of the interradical distance by 5-7 pm and a reduction of the singlet-triplet energy splitting by 3 kcal mol(-1), in good agreement with isodesmic equations, according to which the singlet ground state of 3 is destabilized relative to 1 by 3-4 kcal mol(-1). In contrast to 3,5-borabenzyne (2), which is found to be doubly aromatic, nucleus-independent chemical shifts of 3 are almost identical to that of pyridine, indicating the absence of paramagnetic ring current effects that may be associated with "in-plane antiaromaticity". As compared with 1, the overall perturbation caused by the nitrogen atom in 3 is weak, and four electron, three center interaction is of minor importance in this molecule.
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Affiliation(s)
- Michael Winkler
- Lehrstuhl für Organische Chemie II der Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
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De Proft F, von Ragué Schleyer P, van Lenthe JH, Stahl F, Geerlings P. Magnetic properties and aromaticity of o-, m-, and p-benzyne. Chemistry 2002; 8:3402-10. [PMID: 12203320 DOI: 10.1002/1521-3765(20020802)8:15<3402::aid-chem3402>3.0.co;2-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The relative aromaticities of the three singlet benzyne isomers, 1,2-, 1,3-, and 1,4-didehydrobenzenes have been evaluated with a series of aromaticity indicators, including magnetic susceptibility anisotropies and exaltations, nucleus-independent chemical shifts (NICS), and aromatic stabilization energies (all evaluated at the DFT level), as well as valence-bond Pauling resonance energies. Most of the criteria point to the o-benzyne<m-benzyne<p-benzyne aromaticity order, whereas the relative aromaticity of each isomer with respect to benzene depends on the aromaticity criterion. An additional aromaticity evaluation involved the transition state of the Bergman cyclization of (Z)-hexa-1,5-diyn-3-ene which yields p-benzyne. Dissected NICS calculations reveal an aromatic transition state with a larger total NICS but a smaller NICS(pi) component and thus lower aromaticity than benzene.
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Affiliation(s)
- Frank De Proft
- Eenheid Algemene Chemie, Vrije Universiteit Brussel Faculteit Wetenschappen, Pleinlaan 2, 1050 Brussel, Belgium
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Abstract
The matrix isolation and spectroscopic characterization of two C6F4 isomers, the perfluorinated o-benzyne 4 and the m-benzyne 5, is reported. UV photolysis of tetrafluorophthalic anhydride 6 in solid argon at 10 K results in the formation of CO, CO2, and 1,2-didehydro-3,4,5,6-tetrafluorobenzene (4) in a clean reaction. On subsequent 350 nm irradiation 4 is carbonylated to give the cyclopropenone 7. 1,3-Didehydro-2,4,5,6-tetrafluorobenzene (5) was synthesized by UV irradiation of 1,3-diiodo-2,4,5,6-tetrafluorobenzene (8) via 2,3,4,6-tetrafluoro-5-iodophenylradical 9. Photolysis of 8 in solid neon at 3 K produces good yields of both radical 9 and benzyne 5, while in argon at 10 K no reaction is observed. Thus, the photochemistry in neon at extremely low temperature markedly differs from the photochemistry in argon. The formation of 5 from 8 via 9 is reversible, and annealing the neon matrix at 8 K leads back to the starting material 8. The benzynes 4 and 5 and the radical 9 were characterized by comparison of their matrix IR spectra with density functional theory (DFT) calculations.
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Affiliation(s)
- H H Wenk
- Lehrstuhl für Organische Chemie II der Ruhr-Universität, Bochum, Germany
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Sorkhabi O, Qi F, Rizvi AH, Suits AG. The ultraviolet photochemistry of phenylacetylene and the enthalpy of formation of 1,3,5-hexatriyne. J Am Chem Soc 2001; 123:671-6. [PMID: 11456579 DOI: 10.1021/ja0017312] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The ultraviolet photochemistry of phenylacetylene was studied in a molecular beam at 193 nm. The only primary photofragments observed were HCCH (acetylene) and C(6)H(4). Some of the C(6)H(4) molecules were found to decompose to 1,3,5-hexatriyne and molecular hydrogen. An enthalpy of formation of DeltaH(f) < or = 160 +/- 4 kcal mol(-1) was determined for 1,3,5-hexatriyne from the energetic threshold for this process. This experimentally determined value agrees well with our ab initio calculations performed at the G2 level of theory. Angular distribution measurements for the HCCH + C(6)H(4) channel yielded an isotropic distribution and were attributed to a long-lived intermediate and ground-state dissociation. An exhaustive search yielded no evidence for the phenyl + ethynyl or the atomic hydrogen elimination channels even though these were observed in the pyrolytic studies of phenylacetylene [Hofmann, J.; Zimmermann, G.; Guthier, K.; Hebgen, P.; Homann, K. H. Liebigs Ann. 1995, 631, 1995. Guthier, K.; Hebgen, P.; Hofmann, K. H.; Zimmermann, G. Liebigs Ann. 1995, 637, 1995].
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Affiliation(s)
- O Sorkhabi
- Chemical Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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