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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 28, Number 4
BKCSDE 28(4)
April 20, 2007 

 
Title
DFT Study of p-tert-Butylcalix[5]crown-6-ether Complexed with Alkylammonium Ions
Author
Dongsuk Oh, Jong-In Choe*
Keywords
Calix[5]crown-6-ether, Alkylammonium ions, DFT B3LYP/6-31G(d,p), Endo, Exo
Abstract
The structures and energies of p-tert-butylcalix[5]crown-6-ether (1) and its alkylammonium complexes have been calculated by DFT B3LYP/6-31G(d,p) method. We have studied the binding sites of these host-guest complexes focusing on the p-tert-butylcalix[5]arene pocket (endo) or the crown-6-ether moiety (exo) of 1. The smaller alkylammonium cations have the better complexation efficiency with p-tert-butylcalix[5]crown-6- ether than the bulkier alkylammonium ions. For the sec- and tert-butylammonium ions, the hydrogen-bond distances of the exo-complexes are shorter, therefore, stronger than the endo-cases. This DFT calculated result is in parallel with the trend of the experimental association constants of the branched butylammonium ions.
Page
596 - 600
Full Text
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