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Stereochemistry of the bromine for chlorine exchange following /sup 79/Br(n,. gamma. )/sup 80m/Br and /sup 82m(80m)/Br(IT)/sup 82(80)/Br in diastereomeric 2,3-dichlorobutanes

Journal Article · · J. Phys. Chem.; (United States)
DOI:https://doi.org/10.1021/j100548a002· OSTI ID:7351146

The stereochemistry of bromine for chlorine substitution at asymmetric carbon atoms was studied in the pure liquid diastereomeric 2,3-dichlorobutanes and in organic solutions of these compounds. The reactive bromine species were either energetic (hot) /sup 80m/Br atoms generated via the /sup 79/Br(n,..gamma..)/sup 80m/Br nuclear process or bromine species formed as a result of Coulomb fragmentation of /sup 80m/Br- or /sup 82m/Br-labeled molecules. Distinct differences in the sterospecificity of the Br for Cl exchange have been observed depending on the type of nuclear process by which the reactive bromine species are formed and on the amount and nature of the additives present. In the case of the decay induced /sup 80/Br for Cl exchange the observed results can be explained in terms of a model in which the neutralization time for the Br/sup +/ and the time for radical recombination are the determining factors for the stereochemical course of the exchange process. The Br for Cl exchange initiated by ''hot'' /sup 80m/Br atoms appears to be primarily the result of a ''hot'' one-step replacement reaction, as indicated by the presence of a strong conformational effect on the stereochemical course of the reaction.

Research Organization:
Virginia Polytechnic Inst. and State Univ., Blacksburg
OSTI ID:
7351146
Journal Information:
J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 80:7; ISSN JPCHA
Country of Publication:
United States
Language:
English

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