Comparative analysis of complexation of pesticides (fenitrothion, methylparathion, parathion) and their carboxylic ester analogues by β-cyclodextrin. Theoretical semiempirical calculations

摘要: The complexation by β-cyclodextrin (β-CD) of three organophosphorus pesticides, fenitrothion, parathion and methylparathion, their carboxylic ester analogues was analyzed using PM3 molecular mechanics methods. objective to elucidate structural features energy changes that accompany the could possibly affect hydrolysis process, which is catalyzed β-CD in case esters but inhibited for alkaline medium. fenitrothion further explored, since experiments proved its relatively less progresses mainly through a different pathway than usually accepted. results this study show complex structures involving enable effective interactions between guest carbonyl rim host; methylparathion parathion, however, appear be deeply included cavity β-CD. Therefore conditions nucleophilic attack are favorable not two pesticides. Different geometries resulted depending on mode inclusion cavity, none apparently being prone an β-CD, favoring instead approach external OH− group, agreement with experiment.