ISSN:
0749-1581
Schlagwort(e):
Benzo-crown ethers
;
NOESY and variable-temperature
;
13C NMR
;
Complexation
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The structural changes during the complexation of benzo-crown ethers with Cs+, K+ and Na+ were studied by NOESY and variable-temperature 13C NMR spectroscopy. It was found that, on complexation, the distance between the CH-α and 1-CH2 is reduced in dibenzo-24-crown-8 (DB24C8), dibenzo-18-crown-6 and benzo-15-crown-5. Two mechanisms have been proposed for the distance reduction, the fluttering motion of the benzo group and the elongation of the crown moiety. However, it is concluded that both of these mechanisms seem to play a role in the distance reduction. In the complexed state of DB24C8 with Cs+, Cs+ is predicted to be slightly above the plane of the crown oxygens with respect to DB24C8.
Zusätzliches Material:
9 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/mrc.1260290704
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