Synthesis,Characterization,Bioactivity And Sustained Release Properties Of Metal Complexes Of Triazole Fungicides

Triazole fungicides is high efficiency,broad spectrum,low toxicity,which has more advantages than any other fungicides in agricultural.But the extensive use of it has produced resistance,so,it is imperative to find efficient,highly safe and environmentally friendly fungal fungicides.In recent years,some researchers have found that the coordination of pesticide with transition metals can improve the antifungal activity while reducing the toxicity and the environmental pollution.Based on this,six metal complexes of uniconazole and paclobutrazole as ligands have been synthesized and characterized.The main parts of this work are included as follows:Firstly,the uniconazole(L1)and paclobutrazole(L2)reacted with the transition metal salt in a molar ratio of 2:1 at room temperature for several hours,and we obtained six metal complexes.Then the complexes were characterized by elemental analysis and infrared spectroscopy and the crystal structure of the compounds was determined by X-ray single crystal diffraction.Last,the crystal structures were analyzed by using the SHELXTL program to analyze its structural characteristics,H bond accumulation,and three-dimensional approach.Secondly,the antifungal activities of six obtained metal complexes were studied.The antifungal activity of complexes,ligands and metal salts against the plant pathogenic fungi(Botryosphaeria ribis(?),Botryosphaeria berengriana(?),Wheat gibberellic(?)and Grape anthracnose(?))were carried out by the mycelial growth rate method.And through the experimental data,we evaluated the antifungal activities by two indexes:antibacterial rate and EC50 value(50%inhibiting concentration).The results show that antifungal activities of[CoL14C12]is the most significant among the three metal complexes of uniconazole.In particular,the antifungal activities of Grape anthracnose(?)can reach 11.67 times compared to the conventional triazole fungicide uniconazole,and complexes show a better antifungal activities,too.In the three metal complexes of paclobutrazol,[CuL24Br2]shows best antifungal activities against Botryosphaeria berengriana(?),Wheat gibberellic(?)and Grape anthracnose(?).Finally,the sustained-release properties of the six complexes were determined by HPLC.We determined the HPLC standard curves of the two ligands by configuring different concentrations of standard uniconazole(L1)and paclobutrazol(L2)solution and peak area of the six complexes placed in water for different time periods for slow release,respectively.And the sustained release rate obtained by calculating the relationship between the concentration and the peak area,with the data obtained the time-release rate was plotted to analyze the sustained-release properties.