Three new cobalt (II), nickel (II), and copper (II) complexes [M (nicotinamide)(phenanthroline)(H2O)3]Cl2·3H2O (where M: Co (II), Ni (II) and Cu (II)) have been prepared and characterized by elemental analysis, Fourier transform infrared (FT‐IR), and ultraviolet/visible (UV–Vis) spectroscopy as well as thermal analysis. The molar conductance measurements proved that the complexes were electrolytes. The results obtained from FT‐IR confirm that the metal atoms were coordinated by one nitrogen atom from nicotinamide (NA) ligand, two nitrogen atoms from phenanthroline (Phen), and three oxygen atoms from three different water molecules. The complexes have octahedral structure. thermogravimetry (TGA) and its differential (DTG) analyses confirmed the suggested stereochemistry. Coats–Redfern and Horowitz–Metzger equations were used to calculate kinetic and thermodynamic parameters. Molecular modeling calculations confirm the structural geometry of the complexes, and the data indicate that the complexes are soft with respect to ligands where absolute softness (σ) varied from 5.34 to 13.33 eV, whereas σ for NA and Phen are 5.34 and 8.19 eV, respectively. The ligands and their complexes were assayed for their in vitro antimicrobial activities against some bacterial and fungal strains; the data showed that the complexes were active against some bacterial species compared with NA and Phen. Moreover, complexes and ligands revealed excellent antioxidant properties and could be useful in fighting the free radicals which occur in close connection with cancerous cells.

ABSTRACT. A new series of metal complexes of V(IV), Pd(II), Pt(IV), Ce(IV) and U(VI) with 3-[(3-chlorophenyl)-hydrazono]-pentane-2,4-dione (Cphpd) were synthesized and characterized by elemental analysis, molar conductivity, magnetic moment measurements, UV-vis, FT-IR and 1 H NMR as well as TG-DTG techniques. The data indicated that the Cphpd acts as a bidentate ligand through the hydrazono nitrogen and one keto oxygen. The kinetic parameters have been evaluated by using Coats Redfern (CR) and Horowitz-Metzeger (HM) methods. The thermodynamic data reflected the thermal stability for all complexes. The calculated bond length and the bond stretching force constant, F(U=O), values for UO 2 bond are 0.775 Å and 286.95 Nm −1 . The bond lengths, bond angles, dipole moment and the lowest energy model structure of the complexes have been determined with DFT calculations. The antimicrobial activity of the synthesized ligand and its complexes were screened.

No abstract

No abstract

String of vanadium (IV), zirconium (IV), palladium (II), platinum (IV) and uranium (VI) chelates of 2‐cyano‐2‐[(2‐nitrophenyl)hydrazono]thioacetamide (Cnphta) were prepared and characterized by physicochemical, spectroscopic and thermal analyses. The formulae of the isolated solid complexes were assigned as [VO(Cnphta)2(H2O)]SO4 ⋅ 5H2O (1), [ZrO(Cnphta)2(H2O)]Cl2 ⋅ 4H2O (2), [Pd(Cnphta)2]Cl2 (3), [Pt(Cnphta)2Cl2]Cl2 (4) and [UO2(Cnphta)2](NO3)2 ⋅ 5H2O (5). The infrared assignments clearly showed that Cnphta ligand coordinated as a bidentate feature through the hydrazono nitrogen and the thioacetamide nitrogen for V(IV), Zr(IV) and U(VI) but displayed different behavior for Pd(II) and Pt(IV). Results of the molar conductivities measurements showed that the metal complexes were electrolytes in contrast with Cnphta ligand. The interpretation, mathematical analysis and evaluation of kinetic parameters were also carried out. In addition, the studied ligand and its new chelates were tested for their antimicrobial activity against some human or phytopathogenic microorganisms. The new metal complexes explicated promising antibacterial activity against all tested bacteria especially Staphylococcus aureus and Bacillus subtilis. Regarding the antifungal activity, all metal complexes were able to inhibit the mycelium growth of both tested pathogenic fungi. In particular Zr(IV) and Pt(IV) complexes showed the highest significant fungicidal effect against A. fumigatus similar to positive control.