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Title
Japanese:Chirality sensing of fullerenes using cyclic hosts having a chiral N-substituted porphyrin: A remote substituent effect 
English:Chirality sensing of fullerenes using cyclic hosts having a chiral N-substituted porphyrin: A remote substituent effect 
Author
Japanese: 庄子良晃, 田代健太郎, 相田卓三.  
English: Yoshiaki Shoji, Kenato Tashiro, Takuzo Aida.  
Language English 
Journal/Book name
Japanese:Chirality 
English:Chirality 
Volume, Number, Page Vol. 20    No. 3-4    pp. 420-424
Published date Sept. 2007 
Publisher
Japanese:Wiley 
English:Wiley 
Conference name
Japanese: 
English: 
Conference site
Japanese: 
English: 
Official URL http://onlinelibrary.wiley.com/doi/10.1002/chir.20467/abstract
 
DOI https://doi.org/10.1002/chir.20467
Abstract Cyclic host molecules 12H and 22H, having a chiral N-methylporphyrin unit, include C76 in their asymmetrically distorted π-electronic cavity and are capable of spectral discrimination of the enantiomers of C76 by means of 1H NMR. Although the only structural difference between 12H and 22H is in the para-substituents R on their meso-phenyl groups, the association constant of C76 with 12H is more than twice as large as that with 22H. The ΔH values for the association of C76 with these hosts are hardly different from one another, but a rather big difference exists in their ΔS values (12H, −17.7 ± 0.7 J mol−1; 22H, −26.3 ± 1.0 J mol−1). The difference in ΔS is most likely due to a steric effect of the substituents on the conformational freedom of the hexamethylene linkers. Although the R groups are topologically remote from the binding site, they also affect the resolution of the diastereoisomerically split N-Me signals in the 1H NMR spectra of the hosts upon inclusion of C76. Chirality, 2008.

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