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| Organotin derivatives as well as pyrazole and their derivatives play crucial roles as the active moieties in varieties of agrochemicals. Along with the increasing interest in use of sulfur- or nitrogen-functionalized carboxylic acids to yield organotin carboxylates with various and fascinating structures and different bioactivities, these features encourage the exploitation of the biological activity of organotin carboxylates containing pyrazole. In this paper, a series of organotin 1-phenyl-3,5- dimethylpyrazole-4-carboxylates and 1-(2-pyridyl)-3,5-dimethylpyrazole-4-carboxylates have been obtained and characterized by IR, NMR (1H, 13C and 119Sn) and elemental analysis. The structure of triethyltin 1-phenyl-3,5-dimethylpyrazole-4-carboxylate has been further confirmed by X-ray diffraction crystallography. This complex crystallizes with a molecule of water and forms an infinite 2D network through intermolecular O-H…O and O-H…N hydrogen bonds. Fungicide screening indicates that all complexes display good growth inhibition against Alternaria solani, Cercospora arachidicola, Gibberella zeae, Physalospora piricola and Botrytis cinerea. Moreover, high growth inhibition percentage at 50 μg/ml was observed in vitro in case of triorganotin 1-phenyl-3,5-dimethylpyrazole-4-carboxylates and 1-(2-pyridyl)-3,5-dimethylpyrazole-4-carboxylates. The corresponding EC50 of these highly active triorganotin carboxylates have been detected. The value of EC50 of triethyltin 1-(2-pyridyl)-3,5-dimethylpyrazole-4-carboxylate is only 0.06 μg/ml against Physalospora piricola and 0.14 μg/ml against Gibberella zeae, respectively. |
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| Keywords:organotin carboxylate; 1-aryl-3,5-dimethylpyrazole-4-carboxylic acid; crystal structure; fungicidal activity |
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