Mn(II), Co(II), Zn(II), Fe(III) and U (VI) complexes of 2-acetylpyridine 4N-(2-pyridyl) thiosemicarbazone (HAPT); structural, spectroscopic and biological studies

Thiosemicarbazone-Based Compounds: Cancer Cell Inhibitors with Antioxidant Properties

Thiosemicarbazone-based compounds have attracted significant attention in recent years due to their potential as inhibitors of cancer cell proliferation. They not only exhibit strong antiproliferative effects but also possess antioxidant properties that are crucial in combating oxidative stress linked to cancer progression. This review highlights specific compounds that not only exhibit significantly higher antiproliferative activities but also demonstrate lower toxicity compared to traditional chemotherapy agents. This is important because it suggests that these compounds could provide better treatment options while reducing the side effects often associated with chemotherapy. A detailed analysis of the structure-activity relationships (SARs) reveals that the unique structural features of these compounds play a crucial role in their enhanced effectiveness. Understanding which molecular characteristics contribute to improved activity will be key for future compound design. The findings from this study emphasize the need for further exploration and development of these novel agents. By investigating their biological mechanisms and optimizing their structures, researchers can improve cancer treatment strategies, providing safer and more effective options for patients. Despite substantial previous research on thiosemicarbazones and isothiosemicarbazones, the field still holds many unknowns and opportunities for discovery. Studying coordination chemistry with 3d metal ions and strategically modifying their inner structures may lead to new compounds with promising biological activities and selectivity. Overall, exploring thiosemicarbazones and isothiosemicarbazones as innovative pharmacological agents against cancer could unlock their full potential, significantly enhancing cancer treatment protocols and improving patient survival rates.

Synthesis, Characterization, and Anticancer Activity of Phosphanegold(i) Complexes of 3-Thiosemicarbano-butan-2-one Oxime

Four novel phosphanegold(I) complexes of the type [Au(PR3)(DMT)].PF6 (1-4) were synthesized from 3-Thiosemicarbano-butan-2-one oxime ligand (TBO) and precursors [Au(PR3)Cl], (where R = methyl (1), ethyl (2), tert-butyl (3), and phenyl (4)). The resulting complexes were characterized by elemental analyses and melting point as well as various spectroscopic techniques, including FTIR and (1H, 13C, and 31P) NMR spectroscopy. The spectroscopic data confirmed the coordination of TBO ligands to phosphanegold(I) moiety. The solution chemistry of complexes 1-4 indicated their stability in both dimethyl sulfoxide (DMSO) and a mixture of EtOH:H2O (1:1). In vitro cytotoxicity of the complexes was evaluated relative to cisplatin using an MTT assay against three different cancer cell lines: HCT116 (human colon cancer), MDA-MB-231 (human breast cancer), and B16 (murine skin cancer). Complexes 2, 3, and 4 exhibited significant cytotoxic effects against all tested cancer cell lines and showed significantly higher activity than cisplatin. To elucidate the mechanism underlying the cytotoxic effects of the phosphanegold(I) TBO complexes, various assays were employed, including mitochondrial membrane potential, ROS production, and gene expression analyses. The data obtained suggest that complex 2 exerts potent anticancer activity against breast cancer cells (MDA-MB-231) through the induction of oxidative stress, mitochondrial dysfunction, and apoptosis. Gene expression analyses showed an increase in the activity of the proapoptotic gene caspase-3 and a reduction in the activity of the antiapoptotic gene BCL-xL, which supported the findings that apoptosis had occurred.

Thiosemicarbazone N-Heterocyclic Cu(II) complexes inducing nuclei DNA and mitochondria damage in hepatocellular carcinoma cells

The α-N-Heterocyclic thiosemicarbazones and their metal complexes have been widely investigated as anticancer and antibacterial agents for their broad spectrum of pharmacological properties. Thus, two thiosemicarbazone-based Cu(II) complexes, [Cu₂(ptpc)I₂] (1) and [Cu(qtpc)I] (2) with thiosemicarbazone ligand (ptpc = 2-(di(pyridin-2-yl)methylene)-N-(2-(trifluoromethyl)phenyl)-hydrazine-1-carbothioamide, qtpc = 2-(quinolin-8-ylmethylene)-N-(2-(trifluoromethyl)phenyl)hydrazine-1-carbothioamide) were synthesized and evaluated for their biological activities. Complexes 1 and 2 are superior to cisplatin in vitro antiproliferative activities toward hepatocellular carcinoma cell line with the half maximal inhibitory concentration value of 0.2 and 2 μM, respectively. A series of spectroscopic assays and the DNA cleavage experiments showed that both complexes can change and distort the conformation of DNA. Molecular docking experiment further demonstrated that complex 1 binds to DNA mainly in groove mode. Meanwhile, benefiting from their good liposolubility, complexes 1 and 2 could easily enter cells, which further triggers cell cycle arrest and apoptosis. Moreover, complexes 1 and 2 caused serious mitochondrial damage, associating with increased the level of reactive oxygen species (ROS) and Ca²⁺, decreased adenosine triphosphate (ATP) content and mitochondrial membrane potential (Δψ_m), and transformed mitochondrial morphology. These findings indicated that complexes 1 and 2 might exert their anticancer activity by inducing DNA and mitochondrial damage simultaneously.

Trivalent Cobalt Complexes with NNS Tridentate Thiosemicarbazones: Preparation, Structural Study and Investigation of Antibacterial Activity and Cytotoxicity against Human Breast Cancer Cells

New complexes of trivalent cobalt with substituted thiosemicarbazone ligands having an NNS donor system {HL1 = 4-(4-nitrophenyl)-1-((pyridin-2-yl)methylene)thiosemicarbazide and HL2 = 4-(2,5-dimethoxyphenyl)-1-((pyridin-2-yl)methylene)thiosemicarbazide} were synthesized via the in situ oxidation of divalent cobalt chloride accompanying its addition to the ligands. The complexes C1 and C2 were characterized via elemental (CHNS) analysis and 1H NMR, FT-IR and UV-Vis. spectroscopic data. Further, conductometric studies on the DMF solutions of the complexes indicated their 1:1 nature, and their diamagnetism revealed the low-spin trivalent oxidation state of the cobalt in the complexes. The X-ray diffraction analysis of complex C1 indicated that it crystallizes in the triclinic space group P-1. The metal exhibits an octahedral environment built by two anionic ligands bound via pyridine nitrogen, imine nitrogen and thiol sulfur atoms. The complex is counterbalanced by a chloride ion. In addition, two lattice water molecules were detected in the asymmetric unit of the unit cell. The ligand HL2 (20 mg/mL in DMSO) displayed inhibition zones of 10 mm against both S. aureus and E. coli, and the same concentration of the respective complex raised this activity to 15 and 12 mm against these bacterial strains, respectively. As a comparison, ampicillin inhibited these bacterial strains by 21 and 25 mm, respectively. Screening assay by HL1 on four human cancer cells revealed the most enhanced activity against the breast MCF-7 cells. The induced growth inhibitions in the MCF-7 cells by all compounds (0–100 μg/mL) have been detected. The ligands {HL1 and HL2} and complex C2 gave inhibitions with IC50 values of 52.4, 145.4 and 49.9 μM, respectively. These results are more meaningful in comparison with similar cobalt complexes, but less efficient compared with the inhibition with IC50 of 9.66 μM afforded by doxorubicin. In addition, doxorubicin, HL1 and HL2 induced cytotoxicity towards healthy BHK cells with IC50 values of 36.42, 54.8 and 110.6 μM, but surviving fractions of 66.1% and 62.7% of these cells were detected corresponding to a concentration of 100 μg/mL of the complexes (136.8 μM of C1 and 131.4 μM of C2).

Theoretical Investigation by DFT and Molecular Docking of Synthesized Oxidovanadium(IV)-Based Imidazole Drug Complexes as Promising Anticancer Agents

Vanadium compounds have been set in various fields as anticancer, anti-diabetic, anti-parasitic, anti-viral, and anti-bacterial agents. This study reports the synthesis and structural characterization of oxidovanadium(IV)-based imidazole drug complexes by the elemental analyzer, molar conductance, magnetic moment, spectroscopic techniques, as well as thermal analysis. The obtained geometries were studied theoretically using density functional theory (DFT) under the B3LYP level. The DNA-binding nature of the ligands and their synthesized complexes has been studied by the electronic absorption titrations method. The biological studies were carried with in-vivo assays and the molecular docking method. The EPR spectra asserted the geometry around the vanadium center to be a square pyramid for metal complexes. The geometries have been confirmed using DFT under the B3LYP level. Moreover, the quantum parameters proposed promising bioactivity of the oxidovanadium(IV) complexes. The results of the DNA-binding revealed that the investigated complexes bind to DNA via non-covalent mode, and the intrinsic binding constant (K_b) value for the [VO(SO₄)(MNZ)₂] H₂O complex was promising, which was 2.0 × 10⁶ M⁻¹. Additionally, the cytotoxic activity of the synthesized complexes exhibited good inhibition toward both hepatocellular carcinoma (HepG-2) and human breast cancer (HCF-7) cell lines. The results of molecular docking displayed good correlations with experimental cytotoxicity findings. Therefore, these findings suggest that our synthesized complexes can be introduced as effective anticancer agents.

Orto-hydroxy bioactive schiff base compounds: Design, comprehensive characterization, photophysical properties and elucidation of antimicrobial and mutagenic potentials

Preparation and comprehensive characterization of three Schiff base ligands; with trimethoxy substitution (1E,1'E)-N,N'-(naphthalene-1,5-diyl)bis(1-(3,4,5-trimethoxyphenyl)methanimine, 1, with ortho-hydroxy substitution 6,6'-((1E,1'E)-(naphthalene-1,5-diylbis(azaneylylidene))bis(methaneylylidene))bis(2-methoxyphenol), 2 and 3,4-bis(((E)-2-hydroxy-3-methoxy benzylidene)amino)benzoicacid, 3 and their Ni(II), Cu(II), Co(II), Zn(II), Fe(II), Mn(II) complexes have been reported. Their spectral properties were studied in solution and solid-state by a combination of different analytical techniques; FT-IR spectroscopy, ¹H NMR and ¹³C NMR spectroscopy, elemental analysis and thermal analysis. Diamagnetic and paramagnetic natures of the complexes were also determined by magnetic susceptibility measurements in solid-state. Promising photophysical properties were observed as; A_max. were recorded at 226 nm for 2; at 795 nm for 2-Ni, at 782 nm for 2-Cu, at 784 nm for 2-Co, at 702 nm for 2-Zn, at 784 nm for 2-Fe, at 702 nm for 2-Mn and at 289 nm for 3, at 786 nm for 3-Ni, at 797 nm for 3-Cu, at 746 nm for 3-Co, at 794 nm for 3-Zn, at 699 nm for 3-Fe, at 781 nm for 3-Mn ; and I_max were also recorded at; 380, 490, 725 nm for 2 and 2-Metal; 375 nm, 510 nm, 725 nm for 3 and 3-Metal when excitated at 220 nm. Antibacterial activities against different microorganisms; Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 70603, Staphylococcus aureus ATCC 43,300 (MRSA), Salmonella enteritidis ATTC 13076, Sarcina lutea ATCC 9341, Bacillus cereus ATTC 11778, and antifungal activities against Candida albicans NRRL Y-417 of the compounds 1, 2, 3, 2-Cu, 2-Fe, 3-Zn, 3-Fe were determined. Mutagenic properties of the compounds were also studied and according to the results 2-Cu and 3 have been found non-mutagenic in Ames test but also they have strong antimicrobial potential against pathogen microorganisms. For 2-Cu MIC values were ranging between 0.39 and 0.024 mg/ml and the lowest minimum inhibitory concentration (0.024 mg/ml) was determined against E. coli. The 3 numbered compound revealed strong antimicrobial activity at doses of ranging between 0.39 and 0.097 mg/ml and E. coli was the most sensitive bacterium against this chemical.

8-Hydroxyquinoline derived p-halo N4-phenyl substituted thiosemicarbazones: Crystal structures, spectral characterization and in vitro cytotoxic studies of their Co(III), Ni(II) and Cu(II) complexes

The current paper deals with 8-hydroxyquinoline derived p-halo N4-phenyl substituted thiosemicarbazones, their crystal structures, spectral characterization and in vitro cytotoxic studies of Co(III), Ni(II) and Cu(II) complexes. The molecular structures of the ligands, (E)-4-(4-halophenyl)-1-((8-hydroxyquinoline-2-yl)methylene)thiosemicarbazones (halo = fluoro/chloro/bromo) are determined by single crystal X-ray diffraction method. The crystal structures reveal that the ligands are non-planar and exist in their thioamide tautomeric forms. The various physicochemical investigations of the synthesized complexes reveal metal to ligand stoichiometry to be 1:2 in Co(III) complexes whereas 1:1 in Ni(II) and Cu(II) complexes. The ligands coordinate in a tridentate NNS fashion around Co(III) centers to form an octahedral geometry and square planar geometry around Ni(II) and Cu(II) metal centers. The oxidation of Co(II) to Co(III) is observed on complexation. The synthesized compounds are subjected to in vitro cytotoxicity studies. When compared to bare ligands, the complexes show enhancement of the antiproliferative activity against MCF-7, breast cancer cell lines. The Co(III) complexes of fluoro and bromo derivatives of ligands have displayed remarkable results with roughly two fold increase in their activity in correlation to the standard drug, Paclitaxel. Moreover, the fluorescence microscopy images of cells stained with acridine orange-ethidium bromide suggest an apoptotic mode of cell death.

In vitro and in vivo anticancer activity of a thiourea tripyridyl dinuclear Cu(ii) complex

The framework of the copper complex and its biological analysis.

Synthesis of 2-acetylpyridine-N-substituted thiosemicarbazonates of copper(ii) with high antimicrobial activity against methicillin resistant S. aureus, K. pneumoniae 1 and C. albicans

The basic interest in the present study pertains to developing metal based antimicrobial agents, as several microorganisms have built resistance to the conventional drugs.

Synthesis, spectral characterization, molecular modeling and in vitro antibacterial activity of complexes designed from OO, NO and NN donor Schiff-base ligand [corrected]

A new chelating agent, N'-(4-methoxybenzylidene)-2-oxo-2-(phenylamino)acetohydrazide (H2OMPH) and its complexes with Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Hg(II) and U(IV)O2(2+) ions have been prepared and characterized by conventional techniques. The spectral data indicated that the ligand coordinates as neutral bidentate with Cu(II), Mn(II), U(IV)O2(2+) and Hg(II), neutral tridentate with Ni(II), mononegative tridentate with Co(II) and binegative tetradentate with Zn(II) ions. On basis of magnetic and electronic spectral data an octahedral geometry for Mn(II), Co(II) and Ni(II) complexes and a square planar geometry for Cu(II) complex have been proposed and confirmed by applying geometry optimization and conformational analysis. The protonation constants of H2OMPH and the stepwise stability constants of its complexes are calculated at 298, 308 and 318 k as well as their thermodynamic parameters. Also, the Kinetic parameters (Ea, A, ΔH(*), ΔS(*) and ΔG(*)) were determined for each thermal degradation stage of some complexes using Coats-Redfern and Horowitz-Metzger methods. Moreover, the ligand and some complexes were screened for in vitro antibacterial activity against Staphylococcus epidermalies (St. epid); Streptococcus pyagenies (Strp. py.) as Gram +ve bacteria and Escherichia coli (E. coli); Klebsiella spp. (kleb. spp.) as Gram -ve bacteria using inhibition zone diameter.

Significant photocytotoxic effect of an iron(iii) complex of a Schiff base ligand derived from vitamin B6and thiosemicarbazide in visible light

An iron(iii)–Schiff base complex derived from vitamin B₆and thiosemicarbazide is significantly photocytotoxic to HeLa cancer cells in visible light (400 nm–700 nm) but non-toxic in the absence of light.

Synthesis, characterization, molecular modeling and antioxidant activity of Girard's T thiosemicarbazide and its complexes with some transition metal ions

The chelation behavior of N-{[(allylamino) thiomethyl] hydrazinocarbonylmethyl} trimethylammonium chloride (H3ATHC) towards VO(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+) and UO2(2+) ions have been studied. The structures of the complexes were elucidated using elemental analyses, spectral (IR, UV-visible, (1)H NMR and ESR and mass) as well as magnetic and thermal measurements. The ligand acted as ON bidentate, ONS tridentate donor forming mononuclear complexes. A tetrahedral geometry for Co(2+), square-planar for Ni(2+) and Cu(2+), an octahedral for Zn(2+) and a square-pyramidal arrangement for VO(2+) complexes were proposed, respectively. The EPR spectra of Cu(2+) and VO(2+) complexes confirmed the suggested geometries with values of α(2) and β(2) indicating that the in-plane σ-bonding and in-plane π-bonding are appreciably covalent, and were consistent with very strong in-plane σ bonding in the complexes. Also, the bond length, bond angle, HOMO, LUMO, dipole moment and charges on the atoms have been calculated. Also, the thermal behavior and kinetic parameters were determined using Coats-Redfern and Horowitz-Metzger methods. Furthermore, the synthesized compounds were screened for their superoxide-scavenging activity in the PMS/NADH-NBT system as well as their scavenging effect on ABTS (2,2'-azino-bis(3-ethyl benzthiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl(DPPH) radicals. Among these compounds, the ligand and Zn(2+) complex, exhibited the potent ABTS (2,2'-azino-bis(3-ethyl benzthiazoline-6-sulfonic acid) radical scavenging activity, comparable to that of vitamin C.

Molecular structure and biological studies on Cr(III), Mn(II) and Fe(III) complexes of heterocyclic carbohydrazone ligand

The chelating behavior of the ligand (H2APC) based on carbohydrazone core modified with pyridine end towards Cr(III), Mn(II) and Fe(III) ions have been examined. The (1)H NMR and IR data for H2APC revealed the presence of two stereoisomers syn and anti in both solid state and in solution in addition to the tautomeric versatility based on the flexible nature of the hydrazone linkage leading to varied coordination modes. The spectroscopic data confirmed that the ligand behaves as a monobasic tridentate in Cr(III) and Fe(III) complexes and as neutral tetradentate in Mn(II) complex. The electronic spectra as well as the magnetic measurements confirmed the octahedral geometry for all complexes. The bond length and angles were evaluated by DFT method using material studio program for all complexes. The thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. The antioxidant (DDPH and ABTS methods), anti-hemolytic and cytotoxic activities of the compounds have been screened. Cr(III) complex and H2APC showed the highest antioxidant activity using ABTS and DPPH methods. With respect to in vitro Ehrlich ascites assay, H2APC exhibited the potent activity followed by Fe(III) and Cr(III)complexes.

Synthesis, spectral characterization and biological evaluation of copper(II) and nickel(II) complexes with thiosemicarbazones derived from a bidentate Schiff base

Complexes of copper(II) and nickel(II) of general composition M(L)2X2, have been synthesized with the ligand 1-Tetralone thiosemicarbazone (where L=1-Tetralone thiosemicarbazone and X=Cl(-),1/2SO4(2-)). The molar conductance of the complexes in fresh solution of DMSO lies in the range of 10-20Ω(-1)cm(2)mol(-1) indicating their non-electrolytic behavior. Thus, the complexes may be formulated as [M(L2)X2]. Ligand was characterized by mass, NMR, IR and single crystallographic studies. All the complexes were characterized by elemental analyses, magnetic moments, IR, electronic and EPR spectral studies. The IR spectral data of ligand indicated the involvement of sulfur and azomethine nitrogen in coordination to the central metal ion. The copper(II) and nickel(II) complexes were found to have magnetic moments1.93-1.96BM and 2.91-2.94BM corresponding to one and two unpaired electrons respectively. On the basis of molar conductance, EPR, electronic and infrared spectral studies, a tetragonal geometry has been assigned for Cu(II) chloride complex and trigonal bipyramidal to Cu(II) sulfate complex but an octahedral geometry for Ni(II) complexes. Newly synthesized ligand and its Cu(II) and Ni(II) complexes have also been screened against different bacterial and fungal species.

One dodecahedral bismuth(III) complex derived from 2-acetylpyridine N(4)-pyridylthiosemicarbazone: synthesis, crystal structure and biological evaluation

One dodecahedral bismuth(III) complex [Bi(HL)(NO(3))(3)] (1) (HL = 2-acetylpyridine N(4)-pyridylthiosemicarbazone) has been synthesized and structurally characterized. The analytical data reveals the formation of 1 : 1 (metal : ligand) stoichiometry. The bismuth(III) ion is nine-coordinated by one electron pair (6s(2)) of the bismuth(III) atom, two nitrogen and one sulfur atoms from the N(2)S tridentate ligand and five oxygen atoms from three nitrate ions. Biological studies, carried out in vitro against eight selected bacteria, and four human cancer cells, respectively, have indicated that 1 shows better growth-inhibiting properties. Upon further investigation, 1 might produce cytotoxicity through apoptosis.

Synthesis, computational, spectroscopic, thermal and antimicrobial activity studies on some metal-urate complexes

New sixteen uric acid metal complexes of different stoichiometry, stereo-chemistries and modes of interactions were synthesized using different metals Cr, Mn, Fe, Co, Ni, Cu, Cd, UO(2), Na and K. The synthesized complexes were characterized by elemental analysis, spectral (IR, UV-Vis and ESR) methods, thermal analysis (TG, DTA and DSC) and magnetic susceptibility studies. Molecular modeling calculations were used to characterize the ligation sites of the free ligand. Furthermore, quantum chemical parameters of uric acid such as the energies of highest occupied molecular orbital (E(HOMO)), energies of lowest unoccupied molecular orbital (E(LUMO)), the separation energy (ΔE=E(LUMO)-E(HOMO)), the absolute electronegativity, χ, the chemical potential, P(i), the absolute hardness, η and the softness (σ) were obtained for uric acid. Eight different microbial categories were used to study the antimicrobial activity of the free ligand and ten of its complexes. The results indicate that the ligand and its metal complexes possess antimicrobial properties. The stoichiometry of iron-uric acid complex was studied by using different spectrophotometric methods.

Synthesis, spectroscopic characterization and thermal behavior of metal complexes formed with N'-(1-(4-hydroxyphenyl) ethylidene)-2-oxo-2-(phenylamino) acetohydrazide (H3OPAH)

Complexes of Co(II), Ni(II), Cu(II), Mn(II), Cd(II), Zn(II), Hg(II) and U(IV)O(2)(2+) with N'-(1-(4-hydroxyphenyl) ethylidene)-2-oxo-2-(phenylamino) acetohydrazide (H(3)OPAH) are reported and have been characterized by various spectroscopic techniques like IR, UV-visible, (1)H NMR and ESR as well as magnetic and thermal (TG and DTA) measurements. It is found that the ligand behaves as a neutral bidentate, monoanionic tridentate or tetradentate and dianionic tetradentate. An octahedral geometry for [Mn(H(3)OPAH)(2)Cl(2)], [Co(2)(H(2)OPAH)(2)Cl(2)(H(2)O)(4)] and [(UO(2))(2)(HOPAH)(OAc)(2)(H(2)O)(2)] complexes, a square planar geometry for [Cu(2)(H(2)OPAH)Cl(3)(H(2)O)]H(2)O complex, a tetrahedral structure for [Cd(H(3)OPAH)Cl(2)], [Zn(H(3)OPAH)(OAc)(2)] and [Hg(H(3)OPAH)Cl(2)]H(2)O complexes. The binuclear [Ni(2)(HOPAH)Cl(2)(H(2)O)(2)]H(2)O complex contains a mixed geometry of both tetrahedral and square planar structures. The protonation constants of ligand and stepwise stability constants of its complexes at 298, 308 and 318 K as well as the thermodynamic parameters are being calculated. The bond lengths, bond angles, HOMO, LUMO and dipole moments have been calculated to confirm the geometry of the ligand and the investigated complexes. Also, thermal properties and decomposition kinetics of all compounds are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters (E(a), A, ΔH, ΔS and ΔG) of all thermal decomposition stages have been evaluated using Coats-Redfern and Horowitz-Metzger methods.