Synthesis, spectroscopic characterization and biological activity on newly synthesized copper(II) and nickel(II) complexes incorporating bidentate oxygen–nitrogen hydrazone ligands

Investigation on CT-DNA and Protein Interaction of New Pd(II) Complexes Involving Ceftazidime and 3-Amino-1,2,3-triazole: Synthesis, Characterization, Biological Impact, Anticancer Evaluation, and Molecular Docking Approaches

Two new palladium (II) complexes, [Pd(CAZ)(OH2 )2 ]2+ (1) and [Pd(3-AT)(OH2 )2 ]2+ (2), (CAZ=ceftazidime, and 3-AT=amitrole) were synthesized and studied for their potential as anticancer drugs with low toxicity and high potency. To fully characterize these complexes, we conducted elemental analysis and FT-IR studies. Furthermore, we irradiated the complexes with Indian 60 Co gamma rays and thoroughly evaluated their antimicrobial properties. Our results demonstrate that the inhibitory activity of complexes was significantly enhanced against (G+) bacteria and fungi. Additionally, we probed the complexes' interaction with CT-DNA and BSA using various techniques, including UV-vis spectroscopy, thermal denaturation, viscometry, gel electrophoresis, and molecular docking studies. Our findings conclusively demonstrate that these complexes possess a strong binding interaction with CT-DNA via minor groove binding and/or electrostatic interactions, as well as excellent binding affinity to BSA. Finally, we conducted a cytotoxicity assay that clearly indicates these complexes hold immense promise as cell growth inhibitors against MCF-7 and HCT-116.

I2/DMSO-Promoted Synthesis of Diaryl Sulfide- and Selenide-Embedded Arylhydrazones

Functionalization and derivatization of arylhydrazones are important in pharmaceutical, medicinal, material, and coordination chemistry. In this regard, a facile I₂/DMSO-promoted cross-dehydrogenative coupling (CDC) for direct sulfenylation and selenylation of arylhydrazones has been accomplished utilizing arylthiols/arylselenols at 80 °C. This method provides a metal-free benign route for the synthesis of a variety of arylhydrazones embedded with diverse diaryl sulfide and selenide moieties in good to excellent yield. In this reaction, molecular I₂ acts as a catalyst, and DMSO is utilized as a mild oxidant as well as solvent to produce several sulfenyl and selenyl arylhydrazones through a CDC-mediated catalytic cycle.

Synthesis, Characterization, X-Ray Single-Crystal Structure, Potentiometric Measurements, Molecular Modeling, and Bioactivity Screening of Some Thiosemicarbazones

A series of thiosemicarbazone (TSCN) compounds including ((E)-2-((E)-1-(2-(p-tolyl)hydrazono)propan-2-ylidene)hydrazine-1-carbothioamide (TSC1), (E)-N-ethyl-2-((E)-1-(2-(p-tolyl)hydrazono)propan-2-ylidene)hydrazine-1-carbothioamide (TSC2), and (E)-N-phenyl-2-((E)-1-(2-(p-tolyl)hydrazono)propan-2-ylidene)hydrazine-1-carbothioamide) (TSC3) were synthesized and fully characterized by diverse spectroscopies, such as X-ray single-crystal, infrared, mass, proton nuclear magnetic resonance, and ultraviolet-visible. Potentiometric measurements, molecular modeling, and biological and antitumor activity screening were studied. The thermodynamics and protonation constants of TSC1 as a representative of the synthesized TSCs were calculated and discussed. The solution speciation of different species was studied with pH. The molecular parameters of the optimized structures were calculated and discussed. The X-ray single crystals of TSC2 and TSC3 were established. Considering the antimicrobial activities and correlating structure-activity relationship of the synthesized compounds, the TSC1 molecule was considered a promising candidate as an antifungal agent against Candida albicans. Thus, it would be extremely helpful in the field of medicinal chemistry, particularly as an antimicrobial agent. The results are of significance to the chemistry of antimicrobial agents.

Synthesis and Computationally Assisted Spectroscopic Study of Tautomerism in 3-(Phenyl(2-arylhydrazineylidene)methyl)quinoxalin-2(1H)-ones

The recently developed efficient protocol combining implicit and explicit, accurate quantum mechanical modeling of the condensed state [Katsyuba et al., J. Chem. Phys. 155, 024507 (2021)] is used to describe...

Synthesis and Biological Evaluation of Novel Zn(II) and Cd(II) Schiff Base Complexes as Antimicrobial, Antifungal, and Antioxidant Agents

(E)-N,N-Dimethyl-2-((E-1-(2-(p-tolyl)hydrazono)propan-2-ylidene)hydrazine-1-carbothioamide (DMPTHP) and their Zn(II) and Cd(II) complexes have been synthesized and characterized. Different tools of analysis such as elemental analyses, IR, mass spectra, and 1H-NMR measurements were used to elucidate the structure of the synthesized compounds. According to these spectral results, the DMPTHP ligand behaved as a mononegatively charged tridentate anion. Modeling and docking studies were investigated and discussed. Novel Schiff base (DMPTHP) ligand protonation constants and their formation constants with Cd(II) and Zn(II) ions were measured in 50% DMSO solution at 15°C, 25°C, and 35°C at I = 0.1 mol·dm−3 NaNO3. The solution speciation of different species was measured in accordance with pH. Calculation and discussion of the thermodynamic parameters were achieved. Both log K1 and –ΔH1, for M(II)-thiosemicarbazone complexes were found to be somewhat larger than log K2 and –ΔH2, demonstrating a shift in the dentate character of DMPTHP from tridentate in 1 : 1 chelates to bidentate in 1 : 2; M : L chelates and steric hindrance were generated by addition of the 2nd molecule. The compounds prepared have significant activity as antioxidants, similar to ascorbic acid. It is hoped that the results will be beneficial to antimicrobial agent chemistry. The formed compounds acted as a potent antibacterial agent. Molecular docking studies were investigated and have proved that DMPTHP as antibacterial agents act on highly resistant strains of E. coli and also as an anticancer agent.

Bivalent transition metal complexes of ONO donor hydrazone ligand: Synthesis, structural characterization and antimicrobial activity

Mononuclear transition metal complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with a new hydrazone ligand derived from pyrazine-2-carbohydrazide and 2-hydroxyacetophenone have been synthesized. The isolated complexes were characterized by elemental analysis, spectral and analytical methods including elemental analyses, IR, diffuse reflectance, (1)H-NMR, mass spectra, molar conductance, magnetic moment, ESR, XRD, TG and SEM analysis. From the elemental analyses data, the stoichiometry of the complexes was found to be 1:1 (metal:ligand) having the general formulae [M(HL)(Cl)(H2O)2], [M=Mn(II), Co(II), Ni(II) and Cu(II)] and [M(L)(H2O)], [M=Zn(II) and Cd(II)]. The molar conductance values indicate the nonelectrolytic nature of metal complexes. The IR spectral data suggest that the ligand behaves as tridentate moiety with ONO donor atoms sequence towards central metal ion. The Mn(II), Co(II), Ni(II) and Cu(II) complexes have been assigned a monomeric octahedral geometry whereas tetrahedral to Zn(II) and Cd(II) complexes. The antibacterial and antifungal activities of the ligand and its metal complexes were studied against bacterial species Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis and Streptococcus pyogenes and fungi Candida albicans, Aspergillus niger and Aspergillus clavatus. The activity data show that the metal complexes have a promising biological activity comparable with the parent ligand against all bacterial and fungal species.

Synthesis, biological evaluation and molecular modeling of novel series of pyridine derivatives as anticancer, anti-inflammatory and analgesic agents

This paper presents a combined synthesis; characterization, computational and biological activity studies of novel series of pyridines heterocyclic compounds. The compounds have been characterized by elemental analyses and spectral like IR, (1)H NMR, (13)C NMR and MS studies. Michael addition of substituted-2-methoxycarbonylacetanilide 2a,b on the α-substituted cinnamonitriles 3a-d gave the corresponding 2-pyridone derivatives 5-10. Structures of the titled compounds cited in this article were elucidated by spectrometric data (IR, (1)H NMR, (13)C NMR and MS). The molecular modeling of the synthesized compounds has been drawn and their molecular parameters were calculated. Also, valuable information is obtained from the calculation of molecular parameters including electronegativity, net dipole moment of the compounds, total energy, electronic energy, binding energy, HOMO and LUMO energy. Various in vitro antitumor as well as in vivo anti-inflammatory and analgesic activities of the synthesized compounds were investigated. Evaluation of anti-inflammatory activity of test compounds was performed using carrageenan induced paw edema in rats. All the tested compounds showed moderate to good activity. The SAR results indicate that all compounds showed moderate to good activity, among these 7 and 10 compounds having -N(CH3)2 group are most effective.

Analgesic, Anti-Inflammatory, and Antiplatelet Profile of Hydrazones Containing Synthetic Molecules

Hydrazones are present in many of the bioactive compounds with wide interest because of their diverse pharmacological applications. Hydrazones possess wide variety of biological activities such as anticonvulsant, antidepressant, analgesic, anti-inflammatory, antiplatelet, antimicrobial, anticancer, antihypertensive, anthelmintic, antidiabetic, antiparasitic, and other anticipated activities. This created an interest for researchers towards synthesized variety of hydrazone derivatives for different biological activities. Therefore many researchers have synthesized hydrazone derivatives as target structures for their biological activities. This is paper focuses on the analgesic, anti-inflammatory, and antiplatelet activities of hydrazones.

Synthesis, spectroscopic, molecular orbital calculation, cytotoxic, molecular docking of DNA binding and DNA cleavage studies of transition metal complexes with N-benzylidene-N'-salicylidene-1,1-diaminopropane

Eight mononuclear chromium(III), manganese(II), iron(III), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes of Schiff's base ligand were synthesized and determined by different physical techniques. The complexes are insoluble in common organic solvents but soluble in DMF and DMSO. The measured molar conductance values in DMSO indicate that the complexes are non-electrolytic in nature. All the eight metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic data. The analytical data helped to elucidate the structure of the metal complexes. The Schiff base is found to act as tridentate ligand using N2O donor set of atoms leading to an octahedral geometry for the complexes around all the metal ions. Quantum chemical calculations were performed with semi-empirical method to find the optimum geometry of the ligand and its complexes. Additionally in silico, the docking studies and the calculated pharmacokinetic parameters show promising futures for application of the ligand and complexes as high potency agents for DNA binding activity. The interaction of the complexes with calf thymus DNA (CT-DNA) has been investigated by UV absorption method, and the mode of CT-DNA binding to the complexes has been explored. Furthermore, the DNA cleavage activity by the complexes was performed. The Schiff base and their complexes have been screened for their antibacterial activity against bacterial strains [Staphylococcus aureus (RCMB010027), Staphylococcus epidermidis (RCMB010024), Bacillis subtilis (RCMB010063), Proteous vulgaris (RCMB 010085), Klebsiella pneumonia (RCMB 010093) and Shigella flexneri (RCMB 0100542)] and fungi [(Aspergillus fumigates (RCMB 02564), Aspergillus clavatus (RCMB 02593) and Candida albicans (RCMB05035)] by disk diffusion method. All the metal complexes have potent biocidal activity than the free ligand.

Bivalent transition metal complexes of cetirizine: spectroscopic, equilibrium studies and biological activity

Metal complexes of cetirizine·2HCl (CTZ=2-[2-[4-[(4-chlorophenyl)phenyl methyl]piperazine-1-yl]-ethoxy]acetic acid, dihydrochloride have been prepared and characterized by elemental analyses, IR, solid reflectance, magnetic moment, molar conductance, and UV-Vis spectra. The analytical data of the complexes show the formation of 1:2 [M:L] ratio, where M represents Ni(II), Co(II) and Cu(II) ions, while L represents the deprotonated CTZ ligand. IR spectra show that CTZ is coordinated to the metal ions in a monodentate manner through carboxylate-O atom. Protonation equilibria of CTZ and its metal complexation by some divalent metal ions were determined in aqueous solution at constant ionic strength (0.1 M NaCl) using an automatic potentiometric technique. Thermodynamic parameters for the protonation equilibria of CTZ were calculated and discussed. The stability order of M(II)-CTZ complexes were found to obey Mn(2+)<Co(2+)<Ni(2+)<Cu(2+), in accordance with the Irving-Williams order. The concentration distribution of the complexes in solution is evaluated as a function of pH. The CTZ ligand and its metal complexes were screened for their biological activity against bacterial species (Bacillus subtillis RCMB 010067, Staphylococcus aureus RCMB 010028, Pseudomonas aeuroginosa RCMB 010043, and Escherichia coli RCMB 010052) and fungi as (Aspergillus flavus RCMB 02568, Pencicillium italicum RCMB 03924, Candida albicans RCMB 05031 and Geotricum candidum RCMB 05097). The activity data show that the metal complexes have antibacterial and antifungal activity more than the parent CTZ ligand against one or more bacterial or fungi species. MIC was evaluated for the isolated complexes.

Synthesis and biological evaluation of some novel thiazole compounds as potential anti-inflammatory agents

In the present investigation, furo[2,3-d]thiazol-5(2H)-one 5 was obtained from reaction of thiosemicarbazone derivative 2 with diethyl acetylene dicarboxylate. A series of newly synthesized 2-(hydrazinyl)thiazol-4(5H)-one 6, 7 &8 and 2-(4-(substituted)-thiazol-2-yl)hydrazono derivatives 9a, b &10 were synthesized from treatment of thiosemicarbazone derivative 2 with appropriate α-halogenated compounds. Also, a one pot synthesis of thiazole derivatives 13 &15 was achieved from three components reaction of hydrazone derivative 11 with phenyl isothiocyanate and α-halogenated compounds catalyzed by DMF/KOH. 4-(4-Morpholino phenyl) thiazol-2-amino 17 was obtained via the reaction of acetophenone derivative 1 with thiourea in presence of iodine. The reactivity of 2-aminothiazole 17 toward some electrophilic reagents was investigated. The structure of the newly compounds was confirmed on the basis of elemental analysis and spectral data. The antibacterial activity towards two Gram negative (Proteus mirabilis &Serratia marcesens) and two Gram positive (Staphylococcus aureus &Bacillus cereus) bacteria was investigated. The anti-inflammatory activity was also investigated and the inhibition of the carrageenin-induced oedema by these compounds was established.

Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) new complexes of 5-aminosalicylic acid: spectroscopic, thermal characterization and biological activity studies

The complexing behavior of mesalazine (5-aminosalicylic acid; 5-ASA) towards the transition metal ions namely, Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) have been examined by elemental analyses, magnetic measurements, electronic, IR and (1)H NMR. Thermal properties and decomposition kinetics of all complexes are investigated. The interpretation, mathematical analyses and evaluation of kinetic parameters of all thermal decomposition stages have been evaluated using Coats-Redfern equation. The free ligand and its metal complexes have been tested in vitro against Aspergillus fumigatus and Candida albicans fungi and Pseudomonas aeruginosa, Escherichia coli, Bacillis subtilies and Staphylococcus aureus bacteria in order to assess their antimicrobial potential. The results indicate that the metal complexes are also found to have more antimicrobial activity than the parent 5-ASA drug.

Synthesis, characterization, biological activity and equilibrium studies of metal(II) ion complexes with tridentate hydrazone ligand derived from hydralazine

In the present study, a new hydrazone ligand (2-((2-phthalazin-1-yl)hydrazono)methyl)phenol) prepared by condensation of hydralazine (1-Hydralazinophthalazine) with salicylaldehyde (SAH). The synthesized SAH-hydrazone and its metal complexes have been characterized by elemental analyses, IR, (1)H NMR, solid reflectance, magnetic moment, molar conductance, mass spectra, UV-vis and thermal analysis (TGA). The analytical data of the complexes show the formation of 1:1 [M:L] ratio, where M represents Ni(II), Co(II) and Cu(II) ions, while L represents the deprotonated hydrazone ligand. IR spectra show that SAH is coordinated to the metal ions in a tridentate manner through phthalazine-N, azomethine-N and phenolic-oxygen groups. The ligand and their metal chelates have been screened for their antimicrobial activities using the disc diffusion method against the selected bacteria and fungi. Proton-ligand association constants of (SAH) and the stepwise stability constants of its metal complexes are determined potentiometrically in 0.1 M NaNO(3) at different temperatures and the corresponding thermodynamic parameters were derived and discussed. The order of -ΔG° and -ΔH° were found to obey Mn(2+)<Co(2+)<Ni(2+)<Cu(2+), in accordance with the Irving-Williams order. The complexes were stabilized by enthalpy changes and the results suggest that the complexation is an enthalpy-driven process. The concentration distribution diagrams of the complexes are evaluated.

Ligational behavior of Schiff bases towards transition metal ion and metalation effect on their antibacterial activity

New Schiff bases pyrazine-2-carboxylicacid (phenyl-pyridin-2-yl-methylene)-hydrazide (Hpch-bp) HL(1) and pyrazine-2-carboxylicacid (pyridin-2-ylmethylene)-hydrazide (Hpch-pc) HL(2) derived from condensation of pyrazine carboxylic hydrazide (Hpch) with 2-benzoyl pyridine (bp) or pyridine 2-carbaldehyde (pc) and their transition metal complexes of type ML((1-2)2) have been synthesized, where M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Characterization of ligands and their metal complexes was carried out by elemental analysis, conductimetric studies, magnetic susceptibility, spectroscopic techniques (IR, UV-VIS, NMR, ESR, Mass) and thermogravimetric analysis. The physico-chemical studies revealed octahedral geometry or distorted octahedral geometry around metal ion. These azomethine Schiff base ligands acted as tridentate coordinating through carbonyl, azomethine and pyridine nitrogen present in the ligand. The thermodynamic and thermal properties of the complexes have been investigated and it was observed on the basis of these studies that thermal stability of complexes follows the order Mn<Zn<Cu<Co<Ni. The ligands and their complexes were tested for in vitro antibacterial activity at different concentrations against bacteria viz. Gram positive Bacillus subtilis, Micrococcus luteus and Gram negative Pseudomonas aeruginosa, Pseudomonas mendocina. A marked enhancement in biocidal activity of the ligands under similar experimental conditions was observed as a consequence of coordination with metal ions. The trend of growth inhibition in the complexes was found to be in the order: Cu>Mn>Ni>Co>Zn.

DNA-binding, spectroscopic and antimicrobial studies of palladium(II) complexes containing 2,2'-bipyridine and 1-phenylpiperazine

With the purpose of evaluating the ability of Pd(II) complex to interact with DNA molecule as the main biological target, two new complexes [Pd(bpy)(OH(2))(2)] (1) and [Pd(Phenpip)(OH(2))(2)] (2), where (bpy=2,2'-bipyridine; Phenpip=1-phenylpiperazine), have been synthesized and the binding properties of these complexes with CT-DNA were investigated. The intrinsic binding constants (K(b)) calculated from UV-Vis absorption studies were 3.78×10(3) M(-1) and 4.14×10(3)M(-1) for complexes 1 and 2 respectively. Thermal denaturation has been systematically studied by spectrophotometric method and the calculated ΔT(m) was nearly 5 °C for each complex. All the results suggest an electrostatic and/or groove binding mode for the interaction between the complexes and CT-DNA. The redox behavior of the two complexes in the absence and in the presence of calf thymus DNA has been investigated by cyclic voltammetry. The cyclic voltammogram exhibits one quasi-reversible redox wave. The change in E(1/2), ΔE(p) and I(pc)/I(pa) supports that the two complexes exhibit strong binding to calf thymus DNA. Further insight into the binding of complexes with CT-DNA has been made by gel electrophoresis, where the binding of complexes is confirmed through decreasing the intensity of DNA bands. The two complexes have been screened for their antimicrobial activities using the disc diffusion method against some selected Gram-positive and Gram-negative bacteria. The activity data showed that both complexes were more active against Gram-negative than Gram-positive bacteria. It may be concluded that the antimicrobial activity of the compounds is related to cell wall structure of bacteria.

Bis[N′-(9H-fluoren-9-ylidene)benzohydrazidato-κ2N′,O]copper(II)

In the title complex, [Cu(C₂₀H₁₃N₂O)₂], the Cu^II ion is tetra-coordinated by an N₂O₂ set of two ligands in a distorted recta­ngular-planar geometry. The dihedral angle between the two coordinated five-membered metalla rings is 37.5 (3)°. The mol­ecular configuration is stabilized by two C—H⋯O and two C—H⋯N intra­molecular hydrogen bonds. The crystal packing is dominated by van der Waals inter­actions. Three atoms of the phenyl ring of the benzohydrazidate moiety are disordered over two sets of sites in a 0.625 (18):0.375 (18) ratio.