Hexaflumuron_β-cyclodextrin inclusion complex as improved pesticide formulation: A NMR case study

In the present study, we have tried to characterize the inclusion complex of Hexaflumuron (HFM) with β-cyclodextrin (β-CD) using 1H & 19F NMR experiments. HFM is a pesticide (anti-termite) belonging to benzoylphenylurea family that contains three classes of fluorine. Its' very low aqueous solubility can lead to facile accumulation in water or soil causing rapid poisoning of the environment. Therefore, elimination of HFM requires scavenging agents such as β-CD that can encapsulate HFM resulting in better aqueous solubility. A significant change in 19F and 1H NMR chemical shift, 1H & 19F longitudinal (T₁) and 19F transverse relaxation (T₂) time was observed for HFM in the presence of CD that confirms HFM-CD association. Jobs Plot demonstrated that β-CD was found to form 2:1 inclusion complex with HFM. Association constant was determined from chemical shift titration method using modified Benesi-Hildebrand plot. The present study for the first time provides an insight in understanding formulation of HFM in β-CD enhancingthe solubility giving rise to a possible soil remediation method.