Synthesis, characterization, crystal structure and antimicrobial activity of copper(II) complexes with a thiosemicarbazone derived from 3-formyl-6-methylchromone

Synthesis, crystal structure, characterization and antimicrobial activities of ternary chiral mononuclear Schiff base copper(II) complexes

[CuL1-4(tmen)] is a sequence of four ternary mononuclear Schiff base copper(II) complexes that are derived from L-valine, suitable 5'-substituted-2'-hydroxyacetophenones (where the substituents are -Cl for L1, -Me for L2, -OMe for L3, and -H for L4), and tmen (where tmen-N,N,N',N' tetramethyl ethylenediamine). Without isolating the Schiff base ligand or producing any other intermediate products, all of the complexes were synthesised. These compounds were identified using elemental analysis, molar conductance, UV-Vis, FTIR, EPR, VSM-RT, and CD spectra. Single crystal XRD was used to characterise the structure of Complex 1. The crystalline structure exhibits a distorted square pyramidal shape wherein the Schiff base forms an axial bond with the Cu(II) ion through the ONO-donor, while the chelating ligand tmen exhibits both an equatorial and an axial mode of binding through the NN-donor atoms. Hydrogen bonding and non-covalent CH(methyl)π(phenyl) interaction are two intriguing aspects of compound 1's packing diagram. By calculating the minimum inhibitory concentration (MIC) against harmful bacteria, the synthesised complexes' antimicrobial activity was assessed. According to the bioactivity experiments, the microorganisms employed in this investigation were susceptible to the antibacterial and antifungal properties of copper(II) complexes 1-4. According to the bioactivity experiments, the microorganisms employed in this investigation were susceptible to the antibacterial and antifungal properties of copper(II) complexes 1-4.

Novel Copper(II) Coordination Compounds Containing Pyridine Derivatives of N4-Methoxyphenyl-Thiosemicarbazones with Selective Anticancer Activity

Ten coordination compounds, [Cu(L1)Cl] (C1), [Cu(L1)NO3] (C2), [Cu(L2)Cl] (C3), [Cu(L2)NO3] (C4), [Cu(L3)Cl] (C5), [Cu(L3)NO3] (C6), [Cu(L4)NO3] (C7), [Cu(L4)Cl] (C8), [Cu(L5)Cl] (C9), and [Cu(L5)NO3] (C10), containing pyridine derivatives of N4-methoxyphenyl-thiosemicarbazones were synthesized and characterized. The molecular structure of four compounds was investigated using single crystal X-ray diffraction. Spectral analysis techniques such as FT-IR, 1H NMR, 13C NMR, elemental analysis, and molar conductivity were used for all the synthesized compounds. The tested synthesized compounds were evaluated for their anticancer activity and selectivity against a variety of cancer cell lines, including HL-60, LNCaP, MCF-7, HepG-2, K-562, HeLa, BxPC-3, RD, and MDCK normal cell line. Most compounds demonstrated selective anticancer activity superior to doxorubicin. Notably, all ligands showed high antiproliferative activity against HL-60 cells, with IC50 values between 0.01 and 0.06 µM and a selectivity index as high as 5000. Coordination of copper(II) with ligands HL1 and HL3 notably enhanced antiproliferative activity, lowering the IC50 to 0.03 µM. Additionally, the antioxidant activity of these compounds was assessed, revealing that all tested ligands and most coordination compounds exhibited greater antioxidant activity compared to Trolox, with some ligands showing activity up to 12.3 times higher. Toxicity studies on Daphnia magna indicated low toxicity for the ligands, generally less than doxorubicin, with LC50 values ranging from 13 to 90 µM, suggesting moderate toxicity. Conversely, the coordination complexes were more toxic, with LC50 values between 0.5 and 13 µM.

Advances in chromone-based copper(ii) Schiff base complexes: synthesis, characterization, and versatile applications in pharmacology and biomimetic catalysis

Chromones are well known as fundamental structural elements found in numerous natural compounds and medicinal substances. The Schiff bases of chromones have a much wider range of pharmacological applications such as antitumor, antioxidant, anti-HIV, antifungal, anti-inflammatory, and antimicrobial properties. A lot of research has been carried out on chromone-based copper(ii) Schiff-base complexes owing to their role in the organometallic domain and promise as potential bioactive cores. This review article is centered on copper(ii) Schiff-base complexes derived from chromones, highlighting their diverse range of pharmacological applications documented in the past decade, as well as the future research opportunities they offer.

NiII and CoII binary and ternary complexes of 3-formylchromone: spectroscopic characterization, antimicrobial activities, docking and modeling studies

Reactions of 3-formylchromone (L) with Ni(ii) and Co(ii) ions having different anions (acetate, perchlorate, nitrate, and chloride) yielded a series of binary and ternary octahedral complexes with the general formula [ML n L' m X y (S) a ]Z y ·bS, where M = Ni or Co, n = 1-3, L' = auxiliary ligand = 8-hydroxyquinoline or 1,10-phenanthroline, m = 1 or 2, X = acetate or chloride, y = 0 or 2, S = H2O or MeOH, a = 0-2, Z = nitrate or perchlorate and b = 0-1.5. Elemental and thermal analyses and infra-red, electronic, mass, magnetic susceptibility and molar conductivity measurements were successfully utilized to characterize the structures of the chromone complexes. The chromone ligand acts as a neutral bidentate ligand through its formyl and γ-pyrone oxygen atoms. The obtained complexes were formed with molar ratios 1 : 2 and 1 : 3 M : L for the binary and 1 : 2 : 1 and 1 : 1 : 1 M : L : L' for the ternary complexes. The kinetic parameters of the thermal degradation steps were estimated and explained using the Coats-Redfern equations. The synthesized complexes showed antimicrobial activity with higher activity toward Candida albicans and Bacillus subtilis. Docking studies showed good agreement with the antimicrobial activity. Molecular modeling of the synthesized complexes was performed using Hyperchem at the PM3 level and the calculated structures correlate with the experimental data.

Copper(II) and oxidovanadium(IV) complexes of chromone Schiff bases as potential anticancer agents

We report the synthesis, characterization and biological screening of new chromone Schiff bases derived from the condensation of three 6-substituted-3-formyl-chromones with pyridoxal (HL^1-3) and its Cu(II) complexes [Cu(L^1-3)Cl], 1-3. For the 6-methyl derivative, HL², the V^IVO-complex [VO(L²)Cl] (5), as well as ternary Cu and V^IVO complexes with 1,10-phenanthroline (phen), [Cu(L²)(phen)Cl] (4) and [VO(L²)(phen)Cl] (6), were also prepared and evaluated. Their stability in aqueous medium and radical scavenging activity toward DPPH are screened, with [Cu(L²)(phen)Cl] (4) showing hydrolytic stability and [VO(L²)(phen)Cl] (6) high radical scavenging activity. Spectroscopic studies establish bovine serum albumin (BSA), a model for HSA, as a potential reversible carrier of [Cu(L²)(phen)Cl] in blood with K_BC ≈ 10⁵ M^-1. The cytotoxic activity of a group of compounds is evaluated against a panel of human cancer cell lines of different origin (ovary, cervix, brain and breast) and compared to normal cells. Our results indicate that Cu complexes are more cytotoxic than the ligands but not selective towards cancer cells. The most potent complexes (4 and 6) are further evaluated for their apoptotic potential, induction of reactive oxygen species (ROS) and genotoxicity. Both complexes efficiently triggered cell death through apoptosis as evaluated by DNA morphology and TUNEL assay, increased ROS formation as determined by DCFDA (2',7'-dichlorodihydrofluorescein diacetate) analysis, and induced genotoxic damage as visualized via COMET assay in all cancer cells under study. Therefore, 4 and 6 may be potential precursor anticancer molecules, yet they need to be targeted toward cancer cells.

Overview of the Antioxidant and Anti-Inflammatory Activities of Selected Plant Compounds and Their Metal Ions Complexes

Numerous plant compounds and their metal-ion complexes exert antioxidative, anti-inflammatory, anticancer, and other beneficial effects. This review highlights the different bioactivities of flavonoids, chromones, and coumarins and their metal-ions complexes due to different structural characteristics. In addition to insight into the most studied antioxidative properties of these compounds, the first part of the review provides a comprehensive overview of exogenous and endogenous sources of reactive oxygen and nitrogen species, oxidative stress-mediated damages of lipids and proteins, and on protective roles of antioxidant defense systems, including plant-derived antioxidants. Additionally, the review covers the anti-inflammatory and antimicrobial activities of flavonoids, chromones, coumarins and their metal-ion complexes which support its application in medicine, pharmacy, and cosmetology.

Guedes da Silva MF, Marzano C. Synthesis, Characterization and Biological Activity of Novel Cu(II) Complexes of 6-Methyl-2-Oxo-1,2-Dihydroquinoline-3-Carbaldehyde-4n-Substituted Thiosemicarbazones

Three new 6-methyl-2-oxo-1,2-dihydroquinoline-3-carbaldehyde-thiosemicarbazones-N-4-substituted pro-ligands and their Cu(II) complexes (1, -NH2; 2, -NHMe; 3, -NHEt) have been prepared and characterized. In both the X-ray structures of 1 and 3, two crystallographically independent complex molecules were found that differ either in the nature of weakly metal-binding species (water in 1a and nitrate in 1b) or in the co-ligand (water in 3a and methanol in 3b). Electron Paramagnetic Resonance (EPR) measurements carried out on complexes 1 and 3 confirmed the presence of such different species in the solution. The electrochemical behavior of the pro-ligands and of the complexes was investigated, as well as their biological activity. Complexes 2 and 3 exhibited a high cytotoxicity against human tumor cells and 3D spheroids derived from solid tumors, related to the high cellular uptake. Complexes 2 and 3 also showed a high selectivity towards cancerous cell lines with respect to non-cancerous cell lines and were able to circumvent cisplatin resistance. Via the Transmission Electron Microscopy (TEM) imaging technique, preliminary insights into the biological activity of copper complexes were obtained.

Synthesis and Evaluation of the in vitro Antimicrobial Activity of Triazoles, Morpholines and Thiosemicarbazones

BACKGROUND

Microbial infections is a global public health problem. The aim of this work was to synthesize and evaluate the antimicrobial activity of novel triazoles, morpholines and thiosemicarbazones.

METHODS

Compounds were synthesized using 2,4-Dihydroxyacetophenone and 4-hydroxybenzaldehyde as starting materials. The antimicrobial activity of these compounds against bacteria and yeast was evaluated by the broth microdilution method.

RESULTS

The proposed route for synthesis gave high to moderate yields, moreover these compounds were successfully characterized by 1H NMR, 13C NMR and LC-MS. Antimicrobial testing indicated that the thiosemicarbazone and morphine derivatives had the best antimicrobial activity against the microorganisms tested with minimum inhibitory concentrations (MIC) between 0.29 and 5.30 µM. Thiosemicarbazone derivative (12) was able to inhibit the growth of C. tropicalis, with minimum fungicidal concentration (MFC) of 0.55 µM. In addition, this compound was active against E. coli, S. aureus and S. epidermidis, with MIC values ranging from 0.29 to 1.11 µM. Moreover, the morpholine derivative (15) had an MIC value of 0.83 µM against C. albicans and E. coli.

CONCLUSION

We have efficiently synthesized a series of eleven novel triazoles, thiosemicarbazones and morpholine derivatives using 2,4-Dihydroxyacetophenone and 4-hydroxybenzaldehyde as starting materials. Thiosemicarbazone derivative (12) showed promising antifungal and antibacterial activity and these findings suggest that this compound can be used as scaffolds to design new antimicrobial drugs.

Coumarin centered copper(ii) complex with appended-imidazole as cancer chemotherapeutic agents against lung cancer: molecular insight via DFT-based vibrational analysis

Synthesis and structural characterization of the novel copper complex, DFT based vibrational analysis, DNA binding studies. In vitro cytotoxicity against A549 cancer cell lines and estimation of GSH, ROS, LPO levels, have been reported.

Crystal structures of two hydrazinecarbo-thio-amide derivatives: (E)-N-ethyl-2-[(4-oxo-4H-chromen-3-yl)methyl-idene]hydrazinecarbo-thio-amide hemi-hydrate and (E)-2-[(4-chloro-2H-chromen-3-yl)methyl-idene]-N-phenyl-hydrazinecarbo-thio-amide

The title compounds, C13H13N3O2S·0.5H2O, (I), and C17H14ClN3OS, (II), are hydrazinecarbo-thio-amide derivatives. Compound (I) crystallizes with two independent mol-ecules (A and B) and a water mol-ecule of crystallization in the asymmetric unit. The chromene moiety is essentially planar in mol-ecules A and B, with maximum deviations of 0.028 (3) and 0.016 (3) Å, respectively, for the carbonyl C atoms. In (II), the pyran ring of the chromene moiety adopts a screw-boat conformation and the phenyl ring is inclined by 61.18 (9)° to its mean plane. In the crystal of (I), bifurcated N-H⋯O and C-H⋯O hydrogen bonds link the two independent mol-ecules forming A-B dimers with two R 2 (1)(6) ring motifs, and R 2 (2)(10) and R 2 (2)(14) ring motifs. In addition to these, the water mol-ecule forms tetra-furcated hydrogen bonds which alternately generate R 4 (4)(12) and R 6 (6)(22) graph-set ring motifs. There are also π-π [inter-centroid distances = 3.5648 (14) and 3.6825 (15) Å] inter-actions present, leading to the formation of columns along the c-axis direction. In the crystal of (II), mol-ecules are linked by pairs of N-H⋯S hydrogen bonds, forming inversion dimers with an R 2 (2)(8) ring motif. The dimers are linked by C-H⋯π inter-actions, forming ribbons lying parallel to (210).

Syntheses, crystal structures and antimicrobial activities of Cu(ii), Ru(ii), and Pt(ii) compounds with an anthracene-containing tripodal ligand

Three new Cu(ii), Ru(ii), and Pt(ii) compounds of an anthracene-containing tripodal ligand were synthesized. Their crystal structures was determined by a single-crystal X-ray diffraction method and their antimicrobial activities were investigated.