Synthesis, Spectral, Thermal And Biological Studies Of 4-Cyclohexyl-3-(4-Nitrophenyl)Methyl-1,2,4-Triazolin-5-Thione And Its Copper(Ii) Coordination Compound, [Cucl2(H2o)(2)L-2]

One of the strategies for seeking new biologically active substances is to modify compounds with potential biological activity. In this paper, 1,2,4-triazolin-5-thione derivative (3) was obtained in the cyclization reaction of appropriate thiosemicarbazide (2) as an organic ligand. The copper(II) complex, [CuCl2(H2O)(2)L-2] (L=4-cyclohexyl-3-(nitrophenyl)methyl-1,2,4-triazolin-5-thione) (Cu-3) was prepared in a reaction of free ligand (3) with a CuCl2 center dot 2H(2)O solution in MeOH/EtOH mixture at room temperature. TGA data show that Cu-3 and free ligand are stable at room temperature. Both compounds were screened in vitro for antibacterial and antifungal activities using the broth microdilution method. The obtained complex (Cu-3) showed higher antibacterial effect, especially towards Gram-positive bacteria (with moderate activity and Minimal Inhibitory Concentration MIC = 250-500 mu g/mL) than the free ligand (3) (with mild or no bioactivity and MIC >= 1000 mu g/mL). In turn, yeasts, belonging to Candida albicans, exhibited similar sensitivity to both the copper(II) complex (Cu-3) and the organic ligand (3). The anticandidal activity of these compounds was moderate (MIC = 500 mu g/mL), or, in the case of other Candida spp., lower (MIC >= 1000 mu g/mL).