| Supramolecular chemistry has been extensively studied. Especially, cyclodextrin supramolecular complexes applied in pharmacy have been developed and even some of them have been commercialized. However, cyclodextrin supramolecular complexes applied in agriculture are still in initial phase. Therefore, in this thesis, preparation and characterization of two pesticides and cyclodextrin inclusion complexes have been investigated. And their possible formation mechanisms have been also studied by molecular simulation. In addition, new microspheres from racemic mixtures were developed.Permethrin is a popularly used "over-the-counter" agent which is interesting in a variety of therapeutic areas. However, the poor water-solubility of permethrin seriously limits its wider clinical applications. The present study demonstrates that solubility of permethrin in aqueous solution can considerably increase in the presence ofβ-cyclodextrin (β-CD). Extensive experimental data along with computational modeling reveal the formation of stable permethrin/β-CD inclusion complexes, including Permethrin(β-CD) and Permethrin(β-CD)2, and nano-rods with a [Permethrin(β-CD)2]n chain structure through hydrophobic binding. The formed stable Permethrin(β-CD)2 binding structure can be used as a building block (with a length of 1.425 nm) to construct the nano-rods through self-assembly. The complexation of permethrin withβ-CD significantly improved the bioavailability of permethrin and, therefore, increased the bioactivity.The inclusion behavior ofβ-cyclodextrin with iprodione has been investigated by carrying out some analytical techniques and molecular simulation method. Theβ-cyclodextrin/iprodione inclusion complex has exhibited different spectroscopic features and properties from iprodione. The stoichiometric ratio and stability constant describing the extent of formation of inclusion complexes have been determined by phase-solubility studies. The formation and stoichiometry ofβ-cyclodextrin/iprodione complex were simulated by molecular modeling. The formation ofβ-cyclodextrin/iprodione inclusion complexes resulted in enhanced antifungal activity.A new approach for the formation of microsphere has been achieved by racemates. But their two enantiomerically pure compounds cannot self-assemble into well-defined structures. And the formation of microsphere is related with the chiral center. The solid state NMR experiment shows hydrogen bonding also contributes to the formation of microsphere. |
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