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Atropisomerization of di-para-substituted propyl-bridged biphenyl cyclophanes
JournalArticle (Originalarbeit in einer wissenschaftlichen Zeitschrift)
 
ID 1541679
Author(s) Rotzler, Jurgen; Gsellinger, Heiko; Bihlmeier, Angela; Gantenbein, Markus; Vonlanthen, David; Haussinger, Daniel; Klopper, Wim; Mayor, Marcel
Author(s) at UniBasel Mayor, Marcel
Rotzler, Jürgen
Gsellinger, Heiko
Gantenbein, Markus
Vonlanthen, David
Häussinger, Daniel
Year 2013
Title Atropisomerization of di-para-substituted propyl-bridged biphenyl cyclophanes
Journal Organic and Biomolecular Chemistry
Volume 11
Number 1
Pages / Article-Number 110-8
Abstract The influence of electron donors and electron acceptors of variable strength in the 4 and 4' position of 2 and 2' propyl-bridged axial chiral biphenyl cyclophanes on their atropisomerization process was studied. Estimated free energies [capital Delta]G[double dagger](T) of the rotation around the central biphenyl bond which were obtained from 1H-NMR coalescence measurements were correlated to the Hammett parameters [sigma]p as a measure for electron donor and acceptor strength. It is demonstrated that the resulting nice linear correlation is mainly based on the influence of the different substituents on the [small pi]-system of the biphenyl cyclophanes. By lineshape analysis the rate constants were calculated and by the use of the Eyring equation the enthalpic and entropic contributions were evaluated. Density functional theory calculations show a planar transition state of the isomerization process and the calculated energy barriers based on this reaction mechanism are in good agreement with the experimentally obtained free energies.
Publisher Royal Society of Chemistry
ISSN/ISBN 1477-0520 ; 1477-0539
edoc-URL http://edoc.unibas.ch/dok/A6083385
Full Text on edoc No
Digital Object Identifier DOI 10.1039/C2OB26243F
PubMed ID http://www.ncbi.nlm.nih.gov/pubmed/23059962
ISI-Number WOS:000311974300014
Document type (ISI) Journal Article
 
   

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29/03/2024