The enhanced biological activities of three Zn (II) complexes based on different 1,2,4-triazole fungicides

In order to screen effective fungicides, three Zn (II) complexes, [ZnL41(NO3)(2)]center dot 2H(2)O center dot 2EtOH (1), [ZnL24 (NO3)(2)] (2), and [ZnL43(DMF)(2)](NO3)(2) (3), (L-1 = paclobutrazol, L-2 = diniconazole, and L-3 = hexaconazole), were synthesized and characterized by elemental analysis, FT-IR spectroscopy, and singlecrystal XRD. The antifungal activities of these complexes were then evaluated against four selected fungi using the mycelial growth rate method. The resulting data indicate that all the complexes show the enhanced antifungal activities than the corresponding ligand and mixtures. And, the interactions between the metal salt and ligands in the three complexes seem to be synergistic. According to the study of the influence of the structures on the activity, complex 2 with C=C linkage and 2,4-clichlorophenyl moieties enhances the bioactivity significantly, especially against Wheat gibberellic (II). Density functional theory (DFT) calculations were carried out to help explain the enhanced bioactivity of the Zn (II) complexes. Meanwhile, all complexes are excellent grow-regulators, especially complex 3. The resulting data show that the complexes based on triazole fungicides have the potential applications in agriculture.