The current study involves preparation a number of 1,2,4-Triazol derivatives by the reaction of 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol (A) with different aromatic aldehydes to form the Schiff bases (B, C, D and E). In addition preparation of different complexes (A1, A2, B1 and B2) were prepared from the reaction of A and B Ligands with Ni (II) and Cu (II) metals. All the prepared Compounds and their metal complexes were characterized using: Micro elemental analysis, Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy,1H NMR and conductivity measurements. According to the spectral data of the complexes a tetrahedral geometry was suggested for Ni(II) complexes, Cu(II) complexes exhibit a square planer structure.The antibacterial activities of the above prepared compounds against Proteus mirabilis were estimated using well-diffusion method. The inhibition effect of the prepared compounds on urease activity were studied. Maximum velocity (Vmax), Inhibition force constant (Ki), Michael constant (Km) and percentage of inhibition (i %) values of the enzyme were calculated using line weaver Burk equation. The results showed promising inhibition effect on urease activity. All the prepared compounds showed competitive inhibition since the value maximum velocity (Vmax) was remain constant and Michael constant (Km) increased, except compound (C) which showed non-competitive inhibition since the value Vmax was decreased and Km remain constant.Among all compounds studied in this work, the complexes were exhibit the strongest inhibition effect on urease enzyme, where the Complex (B2) has inhibition force constant (Ki = 0.017 M) and the percentage of inhibition (% i = 97.6).
