Khlood S. Abou-Melha

Elaborated studies on nano-sized homo-binuclear Mn(II), Fe(III), Co(II), Ni(II), and Cu(II) complexes derived from N2O2 Schiff base, thermal, molecular modeling, drug-likeness, and spectral

Abstract A series of new homo-binuclear nano Mn(II), Fe(III), Co(II), Ni(II), and Cu(II) complexes were synthesized using a Schiff base ligand derived by condensation of p-phenylenediamine with 2-hydroxy-1-naphthaldehyde. The prepared complexes were characterized using elemental, thermal analyses, FTIR, 1HNMR, 13CNMR, UV–Vis, XRD, SEM, molar conductance, and magnetic moment measurements. FTIR spectral studies revealed the interaction of the ligand as bi-negative tetra-dentate towards Mn(II) and Fe(III) atoms, whereas the ligand molecule coordinates in neutral tetra-dentate mode towards Co(II), Ni(II), and Cu(II) ions. The geometries proposed are mainly octahedral configuration surrounds the central atoms referring to the electronic spectral data and magnetic measurements. The calculations abstracted from XRD patterns propose the nano-sized complexes. The SEM images show the nano-sized appearance of the particles except for the Ni(II)-complex. Thermo-gravimetric analysis was used to ensure the nature of the presence of solvent molecules attaching to the complexes. Molecular modeling was performed to assert the structural formula proposed for the ligand and some of its complexes. Also, drug-likeness was theoretically estimated to display the probable biological activity of the free ligand through a theoretical comparison with known drugs.

Octahedral Co(II) and Ni(II) complexes of Schiff bases, semicarbazone and thiosemicarbazone, synthesis, biological, spectral, and thermal studies

A new series of cobalt(II) and nickel(II) complexes, [M(ligand)(H2O)2(Y)] (M = Co(II) or Ni(II); Y = Cl−, Br− or NO3 −), containing the Schiff-base semicarbazone and thiosemicarbazone, HL1 and HL2, formed from 4-hydroxycoumarin-3-carbaldehyde have been synthesized. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, infrared, electronic spectra, magnetic susceptibility, and conductivity measurements. An octahedral geometry has been suggested for the complexes. The metal complexes were screened for their antifungal and antibacterial activities on different species of pathogenic fungi and bacteria and their biopotency has been discussed.

Spectral studies on a series of metal ion complexes derived from pyrimidine nucleus, TEM, biological and γ-irradiation effect.

A series of thiouracil complexes was prepared, all the prepared compounds are investigated by all possible tools. The ligand coordinates towards two central atoms as a neutral hexadentate mode. The octahedral structure was proposed with Ni(II), Pt(IV) and UO2(II) complexes. Square-pyramidal and square planar with VO(II) and Pd(II) complexes, respectively. VO(II) complex was irradiated by using Gamma radiation to through a light on the probability of geometry changes with the effect of radiation. The parameters calculated from ESR spectra before and after γ-irradiation reflect the rigidity of the complex towards the effect. Such may discuss the unaffected biological behavior before and after irradiation. XRD patterns were carried out to emphasis on the nature of the particles and the purity of products. The ligand, Pt(IV) and Pd(II) are found in nanometer range. TEM is a sensitive tool used to justify on the microstructure and surface morphology. All the investigated compounds are in nanorange. TG curves reflect a lower thermal stability of all investigated complexes due to the presence of water of crystallization. Finally, a toxic effect was observed with all investigated complexes towards Gram positive bacterium as well as a resistant behavior was observed with Gram negative bacteria.

Elaborated spectral analysis and modeling calculations on Co(II), Ni(II), Cu(II), Pd(II), Pt(II), and Pt(IV) nanoparticles complexes with simple thiourea derivative

A series of metal complexes was synthesized using a simple thiourea derivative. The prepared complexes were characterized using different techniques (FTIR, ESR, X-ray diffraction [XRD], TG/DTA, and TEM). The FTIR spectrum of the ligand shows the presence of its tautomer forms (keto–enol). The ligand coordinates as a neutral bidentate in the Pt(IV), Pd(II), and Pt(II) complexes. In the case of Co(II) and Ni(II) complexes, the ligand is mono-negative bidentate. The proposed complexes are four to six coordinate. The geometries are proposed based on electronic spectral data and magnetic measurements and were verified using other tools. The XRD patterns reflect the nanocrystalline structures except for the Cu(II) complex, which is amorphous. The TEM images for platinum complexes show nanosize particles and homogeneous metal ion distribution on the complex surface. The EPR spectrum of Cu(II) complex verified the octahedral geometry of the complex. Molecular modeling was performed to assign the structural formula proposed for the ligand based on the characterization results. Transmission electron micrographs of the Pt(IV) complex; inset shows the magnified image.

Synthesis, spectral and antimicrobial studies of rare earth metal complexes with Schiff-base hydrazone containing quinoline moiety

The synthesis and characterization of lanthanide(III) complexes with the Schiff-base hydrazone, o-hydroxyacetophenone-7-chloro-4-quinoline, (HL) are reported. The complexes were characterized by different physicochemical methods: mass spectrometry, 1H NMR, 13C NMR, and IR, UV-visible, molar conductance and magnetic studies. They have the stoichiometry [Ln(L)2(NO3)]·nH2O where Ln = La(III), Pr(III), Nd(II), Sm(III), Eu(III) and n = 1–3. The spectra of the complexes were interpreted by comparison with the spectrum of the free ligand. The Schiff-base ligand and its metal complexes were tested against one stain Gram +ve bacteria (Staphylococcus aureus), Gram −ve bacteria (Escherichia coli), and Fungi (Candida albicans). The tested compounds exhibited high antimicrobial activities

Spectral and Eukaryotic DNA degradation studies for Ni(II), Pd(II), Pt(IV), Cu(II) and UO22+ complexes derived from thiouracil derivative

A derivative of thiouracil ligand was prepared. Ni(II), Pd(II), Pt(IV), Cu(II) and UO2(2+) complexes were prepared. The elemental and different spectral tools were used for their characterization. A binegative tetradentate mode is the general coordination behavior of the ligand towards all metal ions used. The structural geometries were varied from square-planer (Pt, Pd(II)), square-pyramidal (Cu(II)) and octahedral (UO2(2+)). The geometry optimization implementing the hyperChem reveals that the Cu(II) complex is the most stable one. The thermogravimetric analysis supports the presence of solvent molecules attached with most complexes. The biological investigation was studied on different microorganisms as gram-positive, gram-negative and fungia. The Ni(II) complex shows the most toxic activity towards most organisms used. The degradation effect of DNA was studied by the use of investigated compounds and reveal that the Ni(II) and Pd(II) complexes are the most effective on the DNA degradation.

A Series of Taurocholic Acid Complexes, Spectral, Kinetic, Molecular Modeling, and Antiviral Activity Studies

A series of taurocholic acid complexes was prepared with Cr(III), Fe(III), Co(II), Ni(II), and Cu(II) ions. The IR and Raman spectral data reveal the coordination of acid as mononegative bidentate. NH, and sulfonate (–O−). The bidentate mode of coordination is proposed toward all the metal ions. The electronic spectral data as well as the magnetic moment measurements proposed the octahedral geometry for all investigated complexes. The presence of water molecules was supported by thermal analysis study. ESR spectrum of Cu(II) complex was carried out and acting as a further supporting for the octahedral geometry. The molecular modeling was performed for all complexes to assert on the lower energy content for all isolated complexes in comparing with their free ligand. Such concludes the comparative stability of all isolated complexes. Scanning electron micrography for the Cu(II) complex reveals the particle size is presented in the nano range. An elaborated biological investigation was carried out for all complexes in comparison with their free ligand. The highest antiviral activity was observed with the free ligand and its Ni(II) and Co(II) complexes and moderate activity was observed with Cr(III) and Fe(III) complexes, but the lowest activity was observed with Cu(II) complex.

Simulative aurintricarboxylic acid molecular docking with antitumor activity for its VO(II), Cr(III), Mn(II) and Fe(III) complexes, HF/DFT modeling and elaborated EPR studies

A synthesized aurintricarboxylic acid (ATA) complex was deliberately investigated. Spectral, thermal, theoretical and antitumor studies are accomplished in this study. Elaborated electronic and EPR considerations are introducing parameters support the structural discussion of complexes. Octahedral geometry is proposed for all complexes except VO(II) is a square-pyramidal configuration. Molecular modeling utilizing Gaussian 09 program (HF/DFT) was used to verify the mode of bonding through the optimized geometries as well as essential quantum parameters were calculated using frontier energies (EHOMO & ELUMO). The soft character of the complexes may expect their excellent biological feature. The molecular docking computational achievement displays distinguished bounds of ATA drug with human colorectal carcinoma and human hepatic carcinoma. However, the interaction with human breast carcinoma receptor is completely absent. This behavior may clarify the antitumor activity of the complexes under investigation. The experimental work was supported with docking for carcinoma receptors used experimentally. VO(II) complex displays distinguished inhibition activity toward human carcinoma used. This is pointed to the other important use for ATA drug complexes exceeding the antibacterial field.

Synthesis of Novel VO(II)-Perimidine Complexes: Spectral, Computational, and Antitumor Studies

A series of perimidine derivatives (L1–5) were prepared and characterized by IR, 1H·NMR, mass spectroscopy, UV-Vis, XRD, thermal, and SEM analysis. Five VO(II) complexes were synthesized and investigated by most previous tools besides the theoretical usage. A neutral tetradentate mode of bonding is the general approach for all binding ligands towards bi-vanadyl atoms. A square-pyramidal is the configuration proposed for all complexes. XRD analysis introduces the nanocrystalline nature of the ligand while the amorphous appearance of its metal ion complexes. The rocky shape is the observable surface morphology from SEM images. Thermal analysis verifies the presence of water of crystallization with all coordination spheres. The optimization process was accomplished using the Gaussian 09 software by different methods. The most stable configurations were extracted and displayed. Essential parameters were computed based on frontier energy gaps with all compounds. QSAR parameters were also obtained to give another side of view about the biological approach with the priority of the L3 ligand. Applying AutoDockTools 4.2 program over all perimidine derivatives introduces efficiency against 4c3p protein of breast cancer. Antitumor activity was screened for all compounds by a comparative view over breast, colon, and liver carcinoma cell lines. IC50 values represent promising efficiency of the L4-VO(II) complex against breast, colon, and liver carcinoma cell lines. The binding efficiency of ligands towards CT-DNA was tested. Binding constant (K b) values are in agreement with the electron-drawing character of the p-substituent which offers high K b values. Also, variable Hammetts relations were drawn.