Search

The reaction between 2‐hydroxy‐1‐naphthaldehyde and 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine produced a novel hydrazone ligand (DTHMN), which reacted with Cu(II) and Zn(II) metal ion in molar ratio 1:1, giving octahedral Cu(II)‐DTHMN and tetrahedral Zn(II)‐DTHMN nanosized complexes. The structural geometries have been elucidated on the basis of elemental analysis, nuclear magnetic resonance, infrared, electronic, and electron spin resonance spectra, and magnetic and molar conductance measurements as well as x‐ray diffraction and thermal analysis. TEM analysis showed that Zn(II)‐DTHMN complex has nano‐rode morphology shape. On the other hand, Cu(II)‐DTHMN has sphere shape within nanodomain. The DTHMN ligand exhibits ONN chelating sites through N‐triazine ring, azomethine nitrogen, and deprotonated OH group, forming the mononuclear metal complexes. The synthesized compounds showed a distinct solvatochromic behavior in different polar solvents. A bathochromic alteration is observed when moving from less to high polar solvents, indicating strong solute–solvent interactions accompanied by intramolecular charge transfer (ICT). The ground and excited state dipole moments of these compounds were determined experimentally by solvatochromic shift method using Bilot–Kawski, Lippert–Mataga, Bakhshiev, and Kawski–Chamma–Viallet functions and a microscopic Reichardt's solvent polarity parameter (ETN). The dipole moment is increased significantly upon excitation referring to stabilizing the excited species includes n–π* transition by polarity of solvent. The experimental results are generally consistent with those values obtained by B3LYP/GENECP method at 6‐311G(d,p) basis set for C, H, N, and O atoms and SDD (Stuttgart/Dresden) basis set for the metal atoms. The compounds were tested for antimicrobial efficiency against Gram‐positive bacteria, Gram‐negative bacteria, and fungus strain. Finally, molecular docking was used to study the interactions between donors (the current compounds) and receptors FabH–CoA complex (PDB code: 1HNJ). [ABSTRACT FROM AUTHOR]

ABSTRACT A new Schiff base ligand, HNMPC, was prepared and reacted with some metal ions, including Cu(II), Ni(II), Co(II), Mn(II), and VO(IV). The infrared, electronic, mass, electron spin resonance, nuclear magnetic resonance, thermal and elemental analysis, molar conductance, and magnetic susceptibility measurements were used to characterize the metal complexes. The HNMPC ligand acts as a monoanionic tridentate ONO donor in all complexes, and the coordinating sites are C=Opyridone, C=N, and the phenolate anion. All metal complexes exhibit octahedral configurations, and the results showed that the metal ion:ligand ratio was 1:2. The molecular structural parameters of the ligand and its metal complexes were determined based on the DFT level implemented in the Gaussian 09 program B3LYP/GENECP method at the 6‐311G(d,p) basis set for C, H, N, and O atoms and the SDD (Stuttgart/Dresden) basis set for the metal atoms. The theoretical data were correlated with the experimental results. Gram‐positive bacteria, Gram‐negative bacteria, yeast, and fungi were used to test the current compounds' antimicrobial activity. Investigating the antitumor activity of the ligand and its complexes against the HepG2 cell lines showed encouraging IC50 values that were on par with those of cisplatin. In order to determine the affinity and binding pattern for the synthesized compounds toward the VEGFR‐2 active site, molecular docking studies were conducted, and the results were correlated with antitumor data. Based on the obtained results, future work aimed to synthesize a new category of Schiff bases and their metal complexes derived from the current aminopyridine derivative with diverse aldehydes and ketones. [ABSTRACT FROM AUTHOR]

Reactions of a chromone‐based hydrazone (SalHFC; HL) with Ni(II), Co(II), and Cd(II) ions yielded new solid chelates with the general formula [M(L)X].nZ, M = Ni(II), Co(II) and Cd(II), X = NO3− or OAc−, n = 0.5–2, Z = H2O or EtOH for complexes 1, 3, 4, 6, 7, 8 and [M2(L)(OAc)3X].0.5EtOH.nH2O, M = Ni(II) and Co(II), X = H2O or EtOH, n = 1 or zero for complexes 2 and 5. The synthesized chelates have been successfully characterized by means of different analytical and spectroscopic tools. SalHFC performs as a monoanionic tridentate in all chelates except chelate 2 and 5 (monoanionic tetradentate). Molar conductivity measurements demonstrated a non‐electrolytic manner of all chelates. Nickel(II) and cobalt(II)‐SalHFC chelates displayed tetrahedral geometries whereas cadmium(II) chelates (7 and 8) were octahedral. TG was employed to inspect the thermal degradation patterns of SalHFC‐complexes, and the Coats‐Redfern equations were employed to estimate the kinetic parameters of the thermal degradation steps. Density functional theory (DFT) level implementation in the Gaussian 09 program at B3LYP/6‐311G(d,p) level was efficaciously used to predict the molecular structural properties of SalHFC and its chelates and the theoretical data and experimental findings were then integrated. SalHFC and its chelates displayed anticancer action against the HepG2 cell line and the results were verified by molecular docking studies. [ABSTRACT FROM AUTHOR]

New Zn(II), Cd(II), VO(IV), and UO2(VI) solvatochromic complexes derived from 6‐ethyl‐4‐hydroxy‐2,5‐dioxo‐5,6‐dihydro‐2H‐pyrano[3,2‐c]quinoline‐3‐carboxaldehyde‐semicarbazone ligand (H2L) were synthesized and established by elemental analyses, spectral (IR, UV, NMR, mass spectra), molar conductivity measurements, magnetic susceptibility, and thermal gravimetric analysis (TGA). The ligand coordinates with metal ions through ONO chelating sites, forming an octahedral geometry arrangement, except UO2(VI) that showed pentagonal bipyramidal geometry. Using Coats–Redfern methodology, the kinetic parameters (Ea, A, ΔH, ΔS, and ΔG) of the thermal decomposition steps were calculated and discussed. The complexes showed solvatochromic behavior that used to estimate the ground and excited state dipole moments. Optimization and structural parameters were carried out by density function theory (DFT) at B3LYP/GENECP method at 6‐311G(d,p) basis set for C, H, N, and O atoms and SDD (Stuttgart/Dresden) basis set for the metal atoms and interrelated with the experimental results. The complexes were tested for antimicrobial efficiency against Gram‐positive bacteria, Gram‐negative bacteria, yeast, and fungi. Also, antitumor activity was investigated against HepG‐2 cell line. Finally, the new synthesized complexes upon subjecting to molecular docking and distinguishable results showed outstanding inhibition results of VEGFR‐2 via achieving a high stabilization level inside the largest pocket of 1YWN protein. [ABSTRACT FROM AUTHOR]

A novel semicarbazone NO2 ligand, H2L, was synthesized. The ligand reacted with several metal ions such as Cu(II), Ni(II), Co(II), Fe(III), Cr(III), and Mn(II) in a molar ratio 1:1 (M:L). The H2L ligand and its metal complexes were characterized by electronic, infrared, mass, nuclear magnetic resonance, electron spin resonance spectra, as well as elemental analysis, thermal analysis, molar conductance, and magnetic susceptibility measurements. The Coats–Redfern equations were used to calculate the kinetic parameters (Ea, A, ΔH, ΔS, and ΔG) of the thermal decomposition stages. The H2L ligand acts as dianionic NO2 tridentate in all complexes and coordinates through enolate oxygen, azomethine nitrogen, and deprotonated OH group. The geometrical arrangements in all metal complexes were octahedral geometries. Based on density functional theory (DFT) level implemented in the Gaussian 09 program at B3LYP/6‐311G(d,p) level, the molecular structural parameters of the ligand and its metal complexes were calculated, and the theoretical data were connected with the experimental results. The antimicrobial activity of the current compounds was examined against Gram‐positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram‐negative bacteria (Salmonella typhimurium and Escherichia coli), yeast (Candida albicans), and fungus (Aspergillus fumigatus). The antitumor activity of the ligand and its metal complexes was investigated against HepG2 cell line, which revealed promising IC50 values comparable with that of Cis‐platin. All synthesized compounds were also subjected to molecular docking studies to investigate their binding pattern and affinity for the VEGFR‐2 active site and correlated with antitumor data. [ABSTRACT FROM AUTHOR]

Reaction of 6‐ethyl‐4‐hydroxy‐2,5‐dioxo‐5,6‐dihydro‐2H‐pyrano[3,2‐c]quinoline‐3‐carboxaldehyde (HL) with some metal ions, namely, manganese (II), cobalt (II), nickel (II), zinc (II), cadmium (II), chromium (III), iron (III), cerium (III), oxovanadium (IV), and dioxouranium (VI), yielded a new series of metal complexes; with the general formula, [MHnLAm(H2O)x]Xy·zH2O, n = 0–1, A = NO3− or OAc−, m = 0–2, X = NO3− or SO42−, y = 0–1, and z = 0–3. The metal complexes were characterized by elemental analysis, molar conductance, magnetic moment, thermal analysis, and spectroscopic studies. The HL ligand coordinated with metal ions as monobasic or neutral bidentate via OO donor sites of aldehyde –O and phenolic –OH producing metal complexes with tetrahedral, octahedral, and pentagonal bipyramidal geometries. On the bases of PM3 level, molecular orbital calculations were performed for metal complexes using HyperChem 7.52 program, and the results were correlated with the experimental data. The biological activity of chelating agent and its metal complexes was screened towards Staphylococcus aureus and Bacillus subtilis as Gram‐positive bacteria; Salmonella typhimurium and Escherichia coli as Gram‐negative bacteria, as well as Candida albicans (yeast) and Aspergillus fumigatus (fungus). The antitumor activity of the HL ligand and its metal complexes was tested against Ehrlich Ascites Carcinoma cell line (EAC), which revealed promising IC50 values, comparable with that of cisplatin. Additional QSAR models were developed to predict the biodistribution of a smaller set of metal complexes and the calculated data correlated with antitumor results. [ABSTRACT FROM AUTHOR]

ABSTRACT The current study involved production, comprehensive structural analysis, and physicochemical characterizing of two distinctive complexes namely, Cu(TBH) and Zn(TBH); TBH donor ligand: N′‐(1‐(3,6‐dihydro‐4‐hydroxy‐2,6‐dioxo‐2H‐1,3‐thiazin‐5‐yl)ethylidene)‐2‐hydroxybenzohydrazide) using a wide range of analytical methods, including elemental analysis, UV–Vis, FT‐IR, and 1HNMR spectrometry, molar conductivity and magnetic susceptibility measurements, and thermal analysis. According to the findings, chelation can occur through O, N, and O donor atoms of monoanionic chelator for generating mono‐nuclear chelates with tetrahedral geometry for Cu (II) and octahedral geometry for Zn (II). The anticarcinogenic ability of TBH chelator and its coordinated compounds against human liver cancer (HepG‐2) was investigated. The Cu(TBH) complex was found to have selective and promising anticancer activity against a liver cancer cell line, with lower IC50 (liver carcinoma cell line) and higher IC50 (normal human cell line) values than other produced compounds and standard drugs. Utilizing DFT computations, the molecular structures of the TBH and its complexes were verified, offering a detailed understanding of their quantum chemical characteristics. A quantitative structure–activity relationship (QSAR) model, which illustrates the association between DFT‐computed descriptors and biological activities pIC50, was also created using multiple linear regression (MLR) on the synthesized compounds as anticancer medicines. Additionally, there are no issues with the produced compounds' oral bioavailability according to (ROF) Lipinski's rule of five. Furthermore, docking studies of the synthesized TBH chelator and its chelates with CDK2 kinase have been performed to validate the biological findings. According to our findings, the novel Cu(TBH) nanodrug exhibits considerable cytotoxic activity, prompting further study into its pharmacological profile and exploring its potential in drug development. [ABSTRACT FROM AUTHOR]

New ternary Cu(II)‐chelates with the general formula [ML L′(H2O)x] (NO3)y x (H2O), x = 0–2 and y = 0–1, (L) = 5‐acetyl‐4‐hydroxy‐2H‐1,3‐thiazine‐2,6(3H)‐dione with in the presence of a secondary ligand (L′) [N,O‐donor; 8 hydroxyquinoline or N,N‐donor; 1,10‐phenanthroline and diethethylendiamine]. Characterization of the synthesized complexes was established based on elemental analysis, molar conductance, magnetic susceptibility measurements, spectral (infrared, electronic, mass, 1H‐NMR and ESR) as well as thermal gravimetric analysis (TGA). The complexes exhibited octahedral and square planer geometry. The antimicrobial activity for the studied complexes was tested for different kind of organisms. The geometrical and non‐linear optical parameters of the studied complexes 1–3 are investigated theoretically at the B3LYP/GENECP level of theory. The optimized geometries of the studied complexes are non‐planner as indicated from the dihedral angles. The natural charge population (core, valence and Rydberg), exact electronic configuration, total Lewis, and total non‐Lewis is computed and discussed in terms of natural bond orbitals (NBO) analysis. The calculated EHOMO and ELUMO energies at the same level of theory of the studied complexes were used to calculate the global properties; hardness (η), global softness (S), electrophilicity (ω) and electronegativity (χ). The total dipole moment (μtot), total and anisotropy of polarizability (˂α˃), (Δα) and first hyperpolarizability (˂β˃) values were calculated and compared with urea as a reference compound. From the values of the computed first hyperpolarizability (˂β˃), the ligand and the studied complexes show promising optical properties. [ABSTRACT FROM AUTHOR]