Matrix-isolation decay kinetics of triplet cyclobutanediyls. Observation of both arrhenius behavior and heavy-atom tunneling in C-C bond-forming reactions

Michael Sponsler, Rakesh Jain, Frank D. Corns, Dennis A. Dougherty

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

The ring-closure reactions of a variety of triplet 1,3-cyclobutanediyls (1) have been observed by EPR spectroscopy under matrix-isolation conditions. It is shown that matrix-site effects can be very well modeled by a Gaussian distribution of activation energies with a standard deviation of ca. 0.5 kcal/mol. Several new techniques have been developed to model such dispersive kinetics. Structures 1 with delocalizing substituents (vinyl, phenyl) show conventional Arrhenius behavior, with log A = 6-8 and E a = 1-2 kcal/mol. Fully localized cyclobutanediyls ring close via quantum mechanical tunneling. A model emphasizing the differing well depths of the singlet biradicals is developed to rationalize these contrasting behaviors.

Original languageEnglish (US)
Pages (from-to)2240-2252
Number of pages13
JournalJournal of the American Chemical Society
Volume111
Issue number6
StatePublished - 1989
Externally publishedYes

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Normal Distribution
Spectrum Analysis
Observation
Atoms
Kinetics
Gaussian distribution
Paramagnetic resonance
Activation energy
Spectroscopy

ASJC Scopus subject areas

  • Chemistry(all)

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Matrix-isolation decay kinetics of triplet cyclobutanediyls. Observation of both arrhenius behavior and heavy-atom tunneling in C-C bond-forming reactions. / Sponsler, Michael; Jain, Rakesh; Corns, Frank D.; Dougherty, Dennis A.

In: Journal of the American Chemical Society, Vol. 111, No. 6, 1989, p. 2240-2252.

Research output: Contribution to journalArticle

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