Nashwa M. El-Metwaly

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.

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 of uranyl(II), vanadyl(II) and zirconyl urate complexes, spectral, thermal and biological studies.

Three urate chelations were obtained when uric acid was reacted with UO2(CH3COO)2H2O, VOSO4·XH2O and ZrOCl2·XH2O salts with neutralized with 0.1 M NaOH aqueous media. The 1:2 metal-to-ligand complexes [(UO2)2(C5H2N4O3)2](H2O), [(ZrO)2(H2O)2(C5H2N4O3)2] and [VO((C5H3N4O3)2] were characterized by elemental analyses, molar conductivity, (infrared, Raman and UV-vis) spectra, effective magnetic moment in Bohr magnetons, and thermal analysis (TG/DTG). The urate ligand coordinates as mononegative bidentate donor towards the mononuclear central vanadium atom and coordinated as binegative tetradentate mode towards the binuclear dioxouranium and zirconyl centers. The antibacterial activity of the metal complexes were tested against some kind of bacteria and fungi strains and compared with uric acid. The ligand, ZrO(II) and UO2(II) complex showed a week potential degradation on calf thymus DNA, whereas VO(II) complex slightly degraded the DNA.

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 and Characterization of New Nano-Sized Selenium Compounds to Further Use as Antioxidants Drugs

Here we report the studies on selenium coordination compounds, in particular selenium nanoparticles (Nps), that can be used in pharmacology. The Se Nps were synthesized by three pathways and characterized by FT-IR, XRD, SEM, TEM, and EDX analyses. Сomplexes of Se(0) with alanine, tyrosine, serine, aspartic acid, histidine, and glycine as ligands, are synthesized in a 1: 2 molar ratio. IR spectra of solid complexes indicate that selenium metal is coordinated with the amino and carboxylate groups. The complexes are square planar structures with two amino acids bidentate ligands occupying the corners. Binary complexes of Se Nps with Ala, Tyr, Ser, Asp, His, and Gly react readily with vitamine B3 (nia) affording mixed ligand complexes of the types [Se(AA)2(nia)2], where AA indicates the above aminoacids. These complexes are determined to have a 1 : 2 : 2 (Se : AA : nia) stoichiometry with coordination number 6. The structures of products are studied by FT-IR, Raman and UV-Vis spectra, XRD, SEM/TEM, and TG/DTG. Conductance of the complexes in DMSO indicates their non-electrolytic nature. The complexes demonstrate antioxidant activity with potent scavenging property.

Synthesis of Pyrazolone Derivatives and Their Nanometer Ag(I) Complexes and Physicochemical, DNA Binding, Antitumor, and Theoretical Implementations

Four pyrazolone derivatives and their corresponding silver complexes were synthesized and characterized. Based on elemental analysis, 1 : 2 (M : L) molar ratio was suggested for all inspected complexes. 1H, 13C NMR, mass, UV-Vis, TGA, and IR were the spectral tools used for describing the formulae. Moreover, XRD patterns and SEM pictures were used to evaluate the particle sizes which appeared strongly in nanometer range. CT-DNA study is the major consideration in this study, to test the interacting ability of all synthesized cationic complexes towards cell DNA. Each binding constant was computed and correlated with the Hammett sigma constant. Antitumor activity was examined upon three carcinoma cell lines (MCF-7, HepG2, and HCT116). The high efficiency was recorded towards MCF-7 (breast carcinoma) cell line. Kinetic studies yield essential parameters to assert on the rule of metal atom on thermal feature of organic compounds. Molecular modeling was implemented to optimize the structures of compounds. Also, molecular docking was achieved to obtain a clear view about proposed drug behavior within the affected cells. This was achieved through comparing the calculated internal energy values of all docking complexes. All the tested compounds displayed a significant interaction with breast cancer protein (strong matching with practical result) followed by DNA polymerase protein.

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.