Synthesis of dual-functional pyrazole-based transition metal complexes for improved urease and nitrification activities

• Published in: Inorganica Chimica Acta 2022-12, Vol.543, p.121184, Article 121184
• Main Authors: Li, Ye-Xia, Duan, Wen-Long, Zhai, Xiao-Tong, Luan, Jian, Guo, Fang
• Format: Article
• Language: English
• Subjects: Dual-functional; Inhibitor; Nitrification; Pyrazole-based ligand; Transition metal complex; Urease
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2022.121184

Three new TMCs were successfully synthesized under solution evaporable and mechanochemical methods through variation of two pz-based ligands and three central metal ions. These TMCs may be good candidates for NIs as well as complex 1 can be served as a dual-functional UI and NI inhibitor. [Display omitted] •Three new TMCs derived from pyrazole-based ligands have been synthesized.•TMCs can be prepared by solution evaporable and mechanochemical methods.•The urease and nitrification inhibitive activities of TMCs were investigated.•The structural differences possess a modulating effect on the performances.•Complex 1 can be served as a dual-functional inhibitor. Urease inhibitors (UIs) and nitrification inhibitors (NIs) can greatly reduce nitrogen loss in agriculture soil. However, design and synthesis of an efficient and environmentally dual-functional inhibitor is still a great challenge. Herein, three transition metal complexes (TMCs) based on pyrazole (Hpz) and 3,5-dimethylpyrazole (Hdmpz), namely, [Cu(Hpz)4Cl2] (1), [Zn2(Hdmpz)2(dmpz)2Cl2] (2) and [Co(Hdmpz)2Cl2] (3) have been synthesized and structurally characterized. X-ray diffraction analyses reveal that the three TMCs are 0D supramolecular compounds. Furthermore, the urease and nitrification inhibitive activities of the TMCs are evaluated, showing the excellent nitrification inhibitive activity with the nitrification inhibitive rate is as high as 70.98 % on the 49th day by soil cultivating experiment. Particularly, complex 1 shows significant urease inhibitive activity with half maximal inhibitory concentration (IC50) values of 0.73 ± 0.02 μM (0.5 h) and 0.93 ± 0.01 μM (3 h), which can be served as a dual-functional inhibitor.