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Effect of pressure on [2]pseudorotaxane formation and decomplexation and their corresponding activation volumes.
MedLine Citation:
PMID:  20593805     Owner:  NLM     Status:  PubMed-not-MEDLINE    
In this study, we investigated the effect of pressure on the formation and decomplexation of [2]pseudorotaxanes. High pressure accelerated the formation of [2]pseudorotaxanes in an aprotic nonpolar solvent (CDCl(3)/CD(3)CN) via the slipping approach when using two crown ether/secondary ammonium salt systems: dibenzo[24]crown-8/bis(cyclohexylmethyl)ammonium salt (1a/2a) and tetrabenzo[24]crown-8/dibenzylammonium salt (1b/2b). The influence of pressure on the rate constants for the formation of the [2]pseudorotaxanes 3a and 3b revealed activation volumes (DeltaV(double dagger)) of -2.5 and -4.6 cm(3) mol(-1), respectively, at 303 K and zero pressure. We also investigated the effect of pressure on the decomplexation of the [2]pseudorotaxanes 3a and 3b in a polar solvent (DMSO-d(6)/CDCl(3)), obtaining activation volumes of -0.9 and -0.4 cm(3) mol(-1), respectively, at 303 K and zero pressure. Moreover, we calculated the activation parameters for the decomplexation processes on the basis of transition state theory at each pressure.
Yuji Tokunaga; Nanae Wakamatsu; Norihiro Ohiwa; Osamu Kimizuka; Akihiro Ohbayashi; Koichiro Akasaka; Susumu Saeki; Kenji Hisada; Tatsuhiro Goda; Youji Shimomura
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of organic chemistry     Volume:  75     ISSN:  1520-6904     ISO Abbreviation:  J. Org. Chem.     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-07-30     Completed Date:  2010-11-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2985193R     Medline TA:  J Org Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4950-6     Citation Subset:  -    
Department of Materials Science and Engineering, Faculty of Engineering, University of Fukui, Fukui, 910-8507, Japan.
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