Abstract:
The β-Cyclodextrin (β-CD) complexes of Flumorph and Dimethomorph have been investigated quantitatively by UV measurement. The results showed that the 1:1 inclusion complexes were formed and the formation constants reduced with elevation of temperature. Thermodynamic parameters of the inclusion reaction (ΔH?ΔS?ΔG) were all negative,which suggested that the interaction process between β-CD and the two fungicides were spontaneous, driven by entropy changes of inclusion reaction. Two-dimensional (2D) ROESY NMR experiments were performed to identify the binding geometry of inclusion complex. Both of Z and E isomers of Flumorph formed complexes with β-CD, while only the Z-isomer of Dimethomorph formed complex with β-CD, and the phenyl ring containing fluorine or chlorine atom entered into the cavity of β-CD through the wider rim. Phase-solubility experiments demonstrated that the water-solubility of the two fungicides enhanced in the presence of β-CD. The preliminary bioassay testified that the complexes improved the fungicidal activity. The present study provided a promising outlook for developing water-based formulation of Flumorph and Dimethomorph, increasing its efficacy and improving its formulation.
