On the Trimerization of Cyanoacetylene: Mechanism of Formation of Tricyanobenzene Isomers and Laboratory Detection of Their Radio Spectra

Hopf, Henning; Mlynek, Cornelia; McMahon, Robert J.; Menke, Jessica L.; Lesarri, Alberto; Rosemeyer, Michael; Grabow, Jens‐Uwe

doi:10.1002/chem.201001648

Cited by 7 publications

(5 citation statements)

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“…In 1993, Hopf and Witulski reported that 1,2,4- and 1,2,3-tricyanobenzenes were formed with other products when cyanoacetylene was heated at 160 °C in a sealed tube . Recently, they gave the energies of the products and the proposed intermediates, but no information about the transition states was given …”

Section: Introductionmentioning

confidence: 99%

“…The interesting phenomena of these uncatalyzed thermal cyclotrimerizations of alkynes have attracted some attention. ,− However, several questions remain unanswered because of the scarce experimental and computational evidence. Why can these alkyne cyclotrimerization reactions occur under thermal reaction conditions?…”

Section: Introductionmentioning

confidence: 99%

“…6d Recently, they gave the energies of the products and the proposed intermediates, but no information about the transition states was given. 10 The interesting phenomena of these uncatalyzed thermal cyclotrimerizations of alkynes have attracted some attention. 8,10À12 However, several questions remain unanswered because of the scarce experimental and computational evidence.…”

Section: ' Introductionmentioning

confidence: 99%

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Mechanisms of the Thermal Cyclotrimerizations of Fluoro- and Chloroacetylenes: Density Functional Theory Investigation and Intermediate Trapping Experiments

Yao

2011

J. Am. Chem. Soc.

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Theoretical studies of the mechanisms of the thermal cyclotrimerization of fluoro- and chloroacetylenes, which were reported by Viehe and Ballester, respectively, were conducted with the aid of density functional theory calculations of the (U)B3LYP functional, indicating that the thermal cyclotrimerizations of fluoro- and chloroacetylenes involve tandem processes of regioselectively stepwise [2+2] and stepwise [4+2] cycloadditions. These tandem processes generate 1,2,6-trihalo-Dewar benzenes and 1,2,4-trihalo-Dewar benzenes, which then isomerize to the corresponding benzenes when heated. The rate-determining step of the cyclotrimerizations of haloacetylenes is the dimerization step involving open-shell singlet diradical transition states and intermediates. The substituent effects in the thermal cyclotrimerization of haloacetylenes have been rationalized using frontier molecular orbital theory. The higher reactivity of fluoroacetylenes compared to that of chloroacetylenes is due to the fact that fluoroacetylenes have lower singlet-triplet gaps than chloroacetylenes and more easily undergo dimerization and cyclotrimerization. In this report, additional experiments were performed to verify the theoretical prediction about the cyclotrimerization of chloroacetylene and to trap the proposed 1,4-dichlorocyclobutadiene intermediate. Experiments revealed that the thermal reaction of phenylchloroacetylene at 110 °C gave 1,2,3-triphenyltrichlorobenzene and 1,2,4-triphenyltrichlorobenzene together with a tetramer, cis-1,2,5,6-tetrachloro-3,4,7,8-tetraphenyltricyclo[4.2.0.0(2,5)]octa-3,7-diene. The proposed 1,4-diphenyldichlorocyclobutadiene intermediate in the thermal cyclotrimerization of phenylchloroacetylene was successfully trapped using dienophiles of maleic anhydride and dimethyl acetylenedicarboxylate.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: ' Introductionmentioning

confidence: 99%

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Mechanisms of the Thermal Cyclotrimerizations of Fluoro- and Chloroacetylenes: Density Functional Theory Investigation and Intermediate Trapping Experiments

Yao

2011

J. Am. Chem. Soc.

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“…The synthesis of cytosine from urea and cyanoacetaldehyde was also examined . Cyanoaldehyde may be a product of the hydrolysis of cyanoacetylene, which, in turn, is a derivative of acetylene , (cyanoacetylene can be produced by spark discharge in a CH 4 /N 2 mixture). , Moreover, purine bases can be the product of the reaction of cyanoacetylene with cyanamide through barrierless cyclization through a small number of stages …”

Section: Acetylene In Prebiotic Chemistry Evolutionmentioning

confidence: 99%

Role of Acetylene in the Chemical Evolution of Carbon Complexity

Pentsak,

Murga,

Ananikov

2024

ACS Earth Space Chem.

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Acetylene, among the multitude of organic molecules discovered in space, plays a distinct role in the genesis of organic matter. Characterized by its unique balance of stability and reactivity, acetylene is the simplest unsaturated organic molecule known to have a triple bond. In addition to its inherent chemical properties, acetylene is one of the most prevalent organic molecules found across the Universe, spanning from the icy surfaces of planets and satellites and the cold interstellar medium with low temperatures to hot circumstellar envelopes where temperatures surge to several thousand kelvins. These factors collectively position acetylene as a crucial building block in the molecular diversification of organic molecules and solids present in space. This review comprehensively discusses the formation and expansion of carbon skeletons involving acetylene, ranging from the formation of simple molecules to the origination of the first aromatic ring and ultimately to the formation of nanosized carbon particles. Mechanisms pertinent to both hot environments, such as circumstellar envelopes, and cold environments, including molecular clouds and planetary atmospheres, are explored. In addition, this review contemplates the role of acetylene in the synthesis of prebiotic molecules. A distinct focus is accorded to the recent advancements and future prospects of research into catalytic processes involving acetylene molecules, which is a significant instrument in driving the evolution of carbon complexity in the Universe. The insights garnered from this review underscore the significance of acetylene in astrochemistry and potentially contribute to our understanding of the chemical evolution of the Universe.

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“…So far, the 14 N nuclear quadrupole coupling of nitrile groups were mainly interpreted for planar molecules like tricyanobenzenes and substituted cyanobenzenes. In those molecules, the CN bond is always expected to be polarized due to the difference in electronegativity of the two elements [124,125], while the mesomeric character changes by interactions with the aromatic system to which they are bound. For acetone cyanhydrin, we assume that the electronic withdrawal is mainly reflected in ionic rather than mesomeric changes of the CN bond.…”

Section: N Nuclear Quadrupole Couplingmentioning

confidence: 99%