AN ELECTRON IMPACT STUDY OF SOME C<sub>8</sub>H<sub>I0</sub> ISOMERS

Meyer, Frank; Haynes, Peter; McLean, Stewart; Harrison, Alex G.

doi:10.1139/v65-025

Cited by 13 publications

(1 citation statement)

References 12 publications

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“…7-Methylcycloheptatriene was synthesized according to the methods of Harrison et al and Conrow and purified by distillation. Its structure was identified using the 1 H NMR and normal mass spectra . Other compounds were purchased from Aldrich and used without further purification.…”

Section: Methodsmentioning

confidence: 99%

Unimolecular and Photoinduced Dissociations of Aromatic C₈H₁₀^+• Molecular Ions

2001

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Production of C 7 H 7 + in the unimolecular and photoinduced dissociations of ethylbenzene; methylcycloheptatriene; and o-, m-, and p-xylene ions has been investigated using mass-analyzed ion kinetic energy spectrometry. Both the benzylium and tropylium ions were produced near the reaction threshold, whereas only the benzylium ion was observed at higher internal energy achieved by photoabsorption. Experimental data suggest that interconversion between ethylbenzene and methylcycloheptatriene ions occurs more rapidly than their dissociations near the reaction threshold, whereas xylene ions undergo rate-determining isomerization to the methylcycloheptatriene structure, and dissociation occurs from the ethylbenzene/methylcycloheptatriene ion mixture. The processes occurring at higher internal energy are quite similar, except that the tropylium channel cannot compete against the benzylium channel because either the ethylbenzene ion-to-methylcycloheptatriene ion conversion or the dissociation of the methylcycloheptatriene ion to the tropylium ion is slower than the direct dissociation of the ethylbenzene ion. The above mechanistic picture is in disagreement with the prediction of a dynamic model reported previously. A series of investigations performed for the production of C 7 H 7 + from alkylbenzene ions shows an interesting trend of increasing benzylium production with the increase in the total number of carbon atoms in the alkyl substituents.

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Section: Methodsmentioning

confidence: 99%

Unimolecular and Photoinduced Dissociations of Aromatic C₈H₁₀^+• Molecular Ions

2001

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Metallinduzierte CC‐Einfachbindungsspaltung 5,5‐dialkylsubstituierter Cyclopentadiene durch Metallcarbonylkomplexe der 6. Nebengruppe

et al. 1980

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Metal Induced Cleavage of CC Single Bonds in 5,5-Dialkylcyclopentadienes by 6b-Metal Carbonyl ComplexesReactions of spiroheptadiene 1, 1 methylspiroheptadiene 13, 1 -vinylspiroheptadiene 20, spirononadiene 7, and 5,5-dialkylcyclopentadienes 10 with molybdenum and tungsten complexes of type M(CO),L, lead to cleavage of a CC single bond with formation of o-alkyl-resp. o-acyl-rr-cyclopentadienyl complexes of the corresponding metals. With the analogous chromium complexes products of this type cannot be isolated. Conversions of the spiroheptadienes with substituents in I-position 13 and 20 show, that a methyl group hinders the opening of the nearby CC bond of the three-membered ring in the spiroheptadiene, while the opposite is found for the vinyl group. Crossover experiments with 5,5-dialkylcyclopentadienes 10 reveal an intramolecular transfer of the alkyl groups.Spiroheptadien 1 wird durch Fe,(CO),') oder Ni(CO),,) unter Offnung des Dreirings und Einbau von Kohlenmonoxid in a-Acyl-x-cyclopentadienyl-metallcarbonyle 2 bzw. umgewandelt . Mit Hexacarbonylmolybdan und aktivierten Derivaten des TypsMo(CO),L, entsteht dagegen der uberbruckte a-Alkylkomplex 4. Die kurze Briicke des Komplexes 4 fuhrt zu merklichen Def~rmationen~), die auffallende spektroskopische Abweichungen gegenuber den offenkettigen Analoga 6 zur Folge haben4).Komplexe des Typs Mo(CO),L, vermogen auch das weniger gespannte Spirononadien 7 unter Offnung des Funfrings und Ausbildung des tetramethylenuberbriickten Alkylkomplexes 5 umzuwandeln '). Mit Ni(CO), kann dagegen eine derartige Ringoffnungsreaktion nicht eingeleitet werden2). Auch Fe2(CO), bildet mit Spirononadien 7 zunachst nur den Tricarbonyleisen-Komplex 8 des unveranderten Liganden5), der erst 0

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Ringöffnende Carbonylierung des Spiro[2.4]hepta‐4,6‐dien‐Systems mit Tetracarbonylnickel

1980

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Ring Opening and Carbonylation of the Spiro[2.41hepta-4,6-diene System with TetracarbonylnickelNi(CO),-induced opening of the three-membered ring in spiro[2.4]hepta-4,6-diene (1) is directed by methyl and vinyl substituents. While a methyl group in 1-position hinders the opening of the adjacent three-membered ring CC bond, a vinyl group enhances the opening of this bond. Besides bridged o-alkyl-and o-acyl-x-cyclopentadienyl complexes 2, 5, 6, 9, and 10, dinuclear systems 3 and 7 are also formed, containing a p-[I ,5-di(l-S-q-cyclopentadienyl)-3-pentanone] ligand. Formation of this ligand by carbonylation and coupling of two spiroheptadiene units occurs by coordination of a spiroheptadiene molecule to the acyl complex 2 via the nickelocenophanon 14.

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AN ELECTRON IMPACT STUDY OF SOME C₈H_I0 ISOMERS

Cited by 13 publications

References 12 publications

Unimolecular and Photoinduced Dissociations of Aromatic C₈H₁₀^+• Molecular Ions

Unimolecular and Photoinduced Dissociations of Aromatic C₈H₁₀^+• Molecular Ions

Metallinduzierte CC‐Einfachbindungsspaltung 5,5‐dialkylsubstituierter Cyclopentadiene durch Metallcarbonylkomplexe der 6. Nebengruppe

Ringöffnende Carbonylierung des Spiro[2.4]hepta‐4,6‐dien‐Systems mit Tetracarbonylnickel

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AN ELECTRON IMPACT STUDY OF SOME C8HI0 ISOMERS

Cited by 13 publications

References 12 publications

Unimolecular and Photoinduced Dissociations of Aromatic C8H10+• Molecular Ions

Unimolecular and Photoinduced Dissociations of Aromatic C8H10+• Molecular Ions

Metallinduzierte CC‐Einfachbindungsspaltung 5,5‐dialkylsubstituierter Cyclopentadiene durch Metallcarbonylkomplexe der 6. Nebengruppe

Ringöffnende Carbonylierung des Spiro[2.4]hepta‐4,6‐dien‐Systems mit Tetracarbonylnickel

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AN ELECTRON IMPACT STUDY OF SOME C₈H_I0 ISOMERS

Unimolecular and Photoinduced Dissociations of Aromatic C₈H₁₀^+• Molecular Ions

Unimolecular and Photoinduced Dissociations of Aromatic C₈H₁₀^+• Molecular Ions