%0 Journal Article
%T Interaction of Calix[4]arene and Aliphatic Amines: A Combined NMR, Spectrophotometric and Conductimetric Investigation
%A Nachtigall
%A Francine F.
%A Lazzarotto
%A M¨˘rcio
%A Nome
%A Faruk
%J Journal of the Brazilian Chemical Society
%D 2002
%I Sociedade Brasileira de Qu¨Şmica, SBQ
%R 10.1590/S0103-50532002000300002
%X the constants related to the equilibria between calix[4]arene and aliphatic amines in acetonitrile were measured by conductimetric and spectrophotometric methods, and the structures of the salts studied by nmr spectroscopy. in concentrations about 10-4 mol l-1, free ions are at higher proportion, whereas at 10-2 mol l-1 there is an increase of ion-pairs proportion. the values of the constants found for acid-base reactions allow an evaluation of the value of pka for calix[4]arene in acetonitrile as 16.6 pka units. the analysis of data agrees with a proposal of exo-calix ammonium ion.
%K calixarenes
%K supramolecular chemistry
%K interactions of amines.
%U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0103-50532002000300002&lng=en&nrm=iso&tlng=en