%0 Journal Article
%T Synthesis, Solid and Solution Studies of Paraquat Dichloride Calixarene Complexes. Molecular Modelling
%A Garc¨ªa-Sosa
%A Irma
%A Ram¨ªrez
%A Flor de Mar¨ªa
%J Journal of the Mexican Chemical Society
%D 2010
%I Sociedad Qu¨ªmica de M¨¦xico
%X the interaction of the herbicide paraquat dichloride (pq, substrate) with p-tert-butylcalix[6, 8]arenes (l, receptor) was investigated in both the solution and solid states. the isolated paraquat calixarene complexes were characterised by uv-visible, 1h nmr, esi-ms, luminescence and ir spectroscopies and elemental analysis. the stoichiometry of complexes 1 and 2 was 1:1 (1 herbicide:1 calixarene) and both revealed a biexponential luminescence decay with lifetimes depending on the size and the conformational particularity of the calixarenes. molecular modelling suggested that both calixarenes interact with the herbicide through cation-¦Ð interaction. pq is included in the p-tert-butylcalix[8]arene cavity, a situation favoured by its pinched conformation in polar solvent while it is partially included in the p-tert-butylcalix[6]arene cavity because of its in-out cone conformation. the theoretical results, in particular using mopac procedures, were in agreement with the experimental findings.
%K parent calixarenes
%K pesticides
%K phosphorescence
%K augmented molecular mechanics calculations
%K conflex.
%U http://www.scielo.org.mx/scielo.php?script=sci_abstract&pid=S1870-249X2010000300003&lng=en&nrm=iso&tlng=en