Publication in Inorganic Chemistry Communications

Synthesis, crystal structures, and anti-pathogenic activity of cobalt(II) and zinc(II) N-phenylpiperidine-1-carbothioamide complexes against Fusarium oxysporum

Authors: Ahmed B.M. Ibrahim, Zdeněk Trávníček, Ghada Abd-Elmonsef Mahmoud

Full-text: https://doi.org/10.1016/j.inoche.2025.115798

 

Preparation of cobalt(II) and zinc(II) complexes with an asymmetric thiourea ligand, N-phenylpiperidine-1- carbothioamide, (L), was achieved. The composition and structure of the complexes, [CoL₂Cl₂] (1) and [ZnL₂Cl₂] (2), were determined using various techniques, including single-crystal X-ray diffraction. X-ray structural analysis revealed a distorted tetrahedral arrangement in the vicinity of the central metal atoms, with coordination involving two thioamide (L) ligands through their sulfur atoms and two chlorido ligands. Fusarium oxysporum is one of the most damaging phytopathogens, causing substantial economic losses. Excessive application of commercial antifungals promotes microbial resistance, making the search for new agents essential. The bioactivity of the free ligand, the starting metal(II) chlorides, and complexes 1 and 2 (0–200 μg/ml) against Fusarium oxysporum was evaluated, alongside Cycloheximide as a standard. All compounds exhibited higher activities than the standard. The complexes were the most effective anti-Fusarium oxysporum agents, with the highest inhibitions of 46 and 37 mm for 1, and 2, respectively. Experiments on the fungal pathogenicity of wheat seeds indicated complete inhibition by complex 1 (pathogenicity = zero %), while pathogenicity was only 6.7 % with complex 2. The phytotoxicity of these compounds was assessed based on the percentage of wheat germination obtained. Complex 2 demonstrated the best results, being non-toxic to wheat seeds up to 100 μg/ml, but its phytotoxicity at 200 μg/ml resulted in only 73 % wheat germination.