The existence, stability, and isomerization rate of free, unstabilized cyclohexyl cation are addressed by using the decay technique. Labeled cyclohexyl ions, unsolvated and free of counterions, are generated in gaseous and liq. systems by the decay of a constituent atom of multitritiated cyclohexane. The daughter ions possess up to ∼30 kcal mol-1 excess internal energy, being formed in a geometry reminescent of the neutral parent, rather than in the most stable structure of the cyclohexyl cation. The anal. of the tritiated products from the reaction of the decay ions with suitable nucleophiles in different environments provides compelling evidence for the existence of free cyclohexyl ion as a legitimate intermediate having a lifetime of at least 10-8-10-7 s. The cation corresponds to a local min. on the C6H11+ energy surface, whose depth, deduced from the rate of isomerization to the more stable 1-methylcyclopentyl structure, is estd. to be <10 kcal mol-1. The results confirm earlier conclusions from a radiolytic study and provide useful information on the relative reaction rate of free cyclohexyl and 1-methylcyclopentyl cations toward several nucleophiles.

Free Cyclohexyl Cations From the Decay of Tritiated Cyclohexane / Marina, Attina; Cacace, Fulvio; Cipollini, Romano; Speranza, Maurizio. - In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - ISSN 0002-7863. - STAMPA. - 107:17(1985), pp. 4824-4828. [10.1021/ja00303a004]

Free Cyclohexyl Cations From the Decay of Tritiated Cyclohexane

CACACE, Fulvio;CIPOLLINI, Romano;SPERANZA, Maurizio
1985

Abstract

The existence, stability, and isomerization rate of free, unstabilized cyclohexyl cation are addressed by using the decay technique. Labeled cyclohexyl ions, unsolvated and free of counterions, are generated in gaseous and liq. systems by the decay of a constituent atom of multitritiated cyclohexane. The daughter ions possess up to ∼30 kcal mol-1 excess internal energy, being formed in a geometry reminescent of the neutral parent, rather than in the most stable structure of the cyclohexyl cation. The anal. of the tritiated products from the reaction of the decay ions with suitable nucleophiles in different environments provides compelling evidence for the existence of free cyclohexyl ion as a legitimate intermediate having a lifetime of at least 10-8-10-7 s. The cation corresponds to a local min. on the C6H11+ energy surface, whose depth, deduced from the rate of isomerization to the more stable 1-methylcyclopentyl structure, is estd. to be <10 kcal mol-1. The results confirm earlier conclusions from a radiolytic study and provide useful information on the relative reaction rate of free cyclohexyl and 1-methylcyclopentyl cations toward several nucleophiles.
1985
01 Pubblicazione su rivista::01a Articolo in rivista
Free Cyclohexyl Cations From the Decay of Tritiated Cyclohexane / Marina, Attina; Cacace, Fulvio; Cipollini, Romano; Speranza, Maurizio. - In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - ISSN 0002-7863. - STAMPA. - 107:17(1985), pp. 4824-4828. [10.1021/ja00303a004]
File allegati a questo prodotto
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/460746
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 14
social impact