Metal Complex Derivatives of Azole: a Study on Their Synthesis, Characterization, and Antibacterial and Antifungal Activities

Abstract

Four new zinc complex derivatives of azoles and ligands were synthesized and isolated as white air-stable solids and characterized by elemental analyses, thermogravimetric analysis (TGA), infrared spectroscopy, nuclear magnetic resonance (NMR) and mass spectra. The elemental analysis, theoretical calculations and NMR show that the complexes likely have a 1:1 (M:L) stoichiometry and tetrahedral geometry. To evaluate the biological activity of the complexes and to discuss the role of metal ions and structural properties, the ligands and their metal complexes have been studied. Their antimicrobial activity was determined in vitro by agar-well diffusion and broth microdilution against nine bacterial strains and seven fungal strains with clinical relevance. In vitro assays showed that the complexes exhibited moderate antibacterial and/or antifungal activities. The antimicrobial activity was found to be more active for the metal complexes than the ligands. The metal complexes that contained copper and cobalt, respectively, displayed notable antibacterial and antifungal effects against all the tested bacterial strains. The minimum inhibitory concentration 50 (MIC 50 ) values were in the range 2454-0.7 μg mL -1 . Metal complexes were more effective at inhibiting bacteria than fungi. The results could provide a high-potential solution for antimicrobial growth resistance, for both bacteria and fungi.

Biological Activity of New Cichoric Acid–Metal Complexes in Bacterial Strains, Yeast-Like Fungi, and Human Cell Cultures In Vitro

“…In our study C. albicans appears to be the most sensitive on CA-Co and CA-Ni treatments. Castillo et al indicate that chemical complexes with Co and Cu have better antimicrobial effect as compared to those containing zinc [38]. In our study, the similar results for CA-Cu were obtained for C. albicans, E. coli, P. vulgaris, and S. epidermidis.…”

Development of Antibacterial and Antifungal Triazole Chromium(III) and Cobalt(II) Complexes: Synthesis and Biological Activity Evaluations

“…Such results indicate greater rigidity in the chemical bonds in the all complexes confirming the coordination of the metals to the N of the azole [ 27 , 33 ]. Bands are also observed at 3435 and 3429 cm −1 for 2 and 5 , respectively ( Figures S9 and S10 in Supplementary Materials ), that correspond to the stretches of the bond (O-H) in water molecules [ 34 ].…”

“…Previous studies demonstrated that the resulting complexes may have higher antimicrobial activity than the corresponding free azole ligands, and, in some cases, exceeding that of standard test substances (nystatin) [ 25 , 26 ]. In this context, we previously studied the antibacterial and antifungal activities of cobalt(II) and copper(II) complexes derived from benzotriazole, which showed higher antimicrobial activities than the free ligands [ 24 , 27 ]. In line with our results, Sumrra et al recently reported that complexes derived from triazole had antibacterial and antifungal activities higher than the corresponding ligands [ 28 ].…”

Water Dissociation of a Dinuclear Bis(3,5‐dimethylpyrazolyl)methane Copper(II) Complex: X‐ray Diffraction Structure, Magnetic Properties, and Characteristic Absorption of the (CuN2Cl2)2 Core

“…In 2007, the synthesis and crystalline structure of a monomeric compound of L and CuCl 2 , produced by the reaction of N ‐hydroxymethyl‐3,5‐dimethylpyrazole with CuCl 2 in a 2:1 ratio in ethanol, was reported, supporting the work of Mesubi and Anumba. The reaction between L and CuCl 2 , yielding a yellow complex, has also been previously reported, and the compound is considered to be a monomeric compound, as well , , , . However, the yellow complex had not been characterized by single‐crystal X‐ray diffraction, which led us to inquire about the structural identity of this compound.…”

“…Materials and Instruments: All of the reagents and solvents were obtained from commercial sources and were used without further purification. Bis(3,5‐dimethyl‐1‐pyrazolyl)methane ( L ) was synthesized as described in the literature . Fourier transform infrared (FTIR) spectra were recorded with a Thermo Nicolet NEXUS FTIR spectrophotometer, using KBr pellets, from 500 to 4000 cm –1 .…”