Inclusion effects of β-cyclodextrins on the hydrolysis of organophosphorus pesticides

Inclusion effects of β-cyclodextrin ( β-CyD ) and its methyl derivatives on the hydrolysis of organothiophosphate pesticides, such as parathion, methyl parathion and fenitrothion, were investigated in humin-rich alkaline medium.The inclusion effects of β-CyDs were characterized by the multiple linear regression analysis using as descriptors the inclusion depth and orientation of the pesticides, the dissociation constant of CyD-pesticide inclusion complexes and degree of the methylation of the catalytically active secondary hydroxyl groups of the CyDs host cavity. The inclusion-geometrical parameters were estimated by the rotational-strength analysis of the circular dichroiss spectra induced in the included pesticides.