Thiosemicarbazones and Derived Antimony Complexes: Synthesis, Structural Analysis, and In Vitro Evaluation against Bacterial, Fungal, and Cancer Cells

Abstract

Two antimony complexes {[Sb(L1)Cl2] C1 and [Sb(L2)Cl2] C2} with the thiosemicarbazone ligands {HL1 = 4-(2,4-dimethylphenyl)-1-((pyridin-2-yl)methylene)thiosemicarbazide and HL2 = 4-(2,5-dimethoxyphenyl)-1-((pyridin-2-yl)methylene)thiosemicarbazide} were introduced. The structures were elucidated on the basis of a CHNS analysis, spectroscopic techniques (UV-Vis and FT-IR), and DMF solution electrical conductivities. Single crystal X-ray diffraction analysis of complex C1 assigned the complex pseudo-octahedral geometry and triclinic P-1 space group. Only the ligand HL1 and its derived complex C1 displayed antifungal activities against Candida albicans and this activity was enhanced from 10 mm to 21 mm for the respective complex, which is the same activity given by the drug “Amphotericin B”. The ligands HL1 and HL2 gave inhibitions, respectively, of 14 and 10 mm against Staphylococcus aureus and 15 and 10 mm against Escherichia coli; however, complexes C1 and C2 increased these inhibitions to 36 and 32 mm against Staphylococcus aureus and 35 and 31 mm against Escherichia coli exceeding the activities given by the ampicillin standard (i.e., 21 mm against Staphylococcus aureus and 25 mm against Escherichia coli). Against MCF-7 human breast cancer cells, the IC50 values of HL1 (68.9 μM) and HL2 (145.4 μM) were notably enhanced to the values of 34.7 and 37.4 μM for both complexes, respectively. Further, the complexes induced less toxicity in normal BHK cells (HL1 (126.6 μM), HL2 (110.6 μM), C1 (>210.1 μM), and C2 (160.6 μM)). As a comparison, doxorubicin gave an IC50 value of 9.66 μM against MCF-7 cells and 36.42 μM against BHK cells.

Thiosemicarbazonecopper/Halido Systems: Structure and DFT Analysis of the Magnetic Coupling

“…The bands located above 3000 cm −1 are attributed to the υ(OH), υ(NH), υ(NH2) and υ(C=H) stretching vibrations [72,83]. A weak band observed between 3075 and 2970 cm…”

“…In this sense, note the anticonformation exhibited by S and N2 with respect to the N3-C7 bond in free HL and free or coordinated cationic H2L+ forms, which contrasts with the syn conformation in metal complexes where the TSC acts as a tridentate ligand. The bands located above 3000 cm −1 are attributed to the υ(OH), υ(NH), υ(NH 2 ) and υ(C=H) stretching vibrations [72,83]. A weak band observed between 3075 and 2970 cm −1 would correspond to the stretching ν(CH) vibration.…”

“…The bands located above 3000 cm −1 are attributed to the υ(OH), υ(NH), υ(NH2) and υ(C=H) stretching vibrations [72,83]. A weak band observed between 3075 and 2970 cm The strong band observed at 1608 cm −1 mode in the HL free ligand could be attributed to the υ(C=N) stretching modes from the pyridine and azomethine nitrogen atoms and bending vibration of the terminal amino group δ(N4-H).…”

Synthesis, Characterization, and Biological Properties of the Copper(II) Complexes with Novel Ligand: N-[4-({2-[1-(pyridin-2-yl)ethylidene]hydrazinecarbothioyl}amino)phenyl]acetamide

“…The literature indicates that thiosemicarbazones and their copper(II) complexes often demonstrate antimicrobial and antifungal properties [10]. Therefore, the antimicrobial and antifungal characteristics of the synthesized compounds were examined.…”

“…The study of new materials in the field of coordination chemistry is increasing day by day, leading to the discovery of substances with advanced biological properties compared to the drugs currently used in medicinal practice. A class of organic compounds called thiosemicarbazones is expected to be the most promising due to a wide range of biological activities, including antituberculosis [1-4], antineoplastic activity [2], anticancer [5], antioxidant [6], antiviral [7], antimicrobial [8,9], antifungal [1, [10][11][12], anticonvulsant [13][14][15], antiproliferative activity [16], anticancer activity [17]. Interest in this family of compounds has grown significantly over the years, from the first report in 1940 to the thousands of papers published by 2022.…”