الفهرس 
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Abstract
Summary
Pyrano[3,2-c]quinolines are compounds which are formed by fusion of a pyran ring and a quinoline ring. Pyrano[3,2-c]quinoline derivatives are known to be present in many natural alkaloids and possess a range of pharmacological and biological activities. Metal complexes of ligands contain quinolinone moiety have attracted a particular interest because of their biological activities including antimicrobial, antifungal and anticancer activities. Metal ions play vital roles in various biological processes such as their role in the action of different enzymes that catalyze a great variety of reactions. Metal complexes have attracted a significant interest as a result of their biological and pharmaceutical properties.
There is not any previous work described the metal complexes with pyrano[3,2-c]quinolines moiety, therefore, the object of the present work is to study the chelating behavior 6-ethyl-4-hydroxy-2,5-dioxo-5,6-dihydro-2H-pyrano[3,2-c]quinoline-3-carboxaldehyde, HL ligand, towards copper(II), manganese (II), cobalt(II), nickel(II), zinc(II), cadmium(II), chromium(III), iron(III), cerium(III), oxovanadium(IV) and dioxouranium(VI) ions.
The HL ligand was prepared and elucidated by elemental analysis, IR, 1H-NMR, 13C-NMR, mass and electronic spectra.
The chelating behavior of HL ligand was studied towards Cu(II) metal ion with different anions (OAc–, NO3–, SO42–, ClO4–, Cl– and Br–) in absence and presence of auxiliary ligands (L′); N,O-donor; or N,N-donor; to form binary and ternary Cu(II)-chelates.
In addition, the HL ligand was coordinated with manganese (II), cobalt(II), nickel(II), zinc(II), cadmium(II), chromium(III), iron(III), cerium(III), oxovanadium(IV) and dioxouranium(VI) ions in a molar ratio (1:1, ligand: metal ion) .
The newly prepared metal complexes of the present ligand was identified by elemental analyses, infrared, electronic, mass, 1H-NMR, 13C-NMR and ESR spectra as well as magnetic susceptibility measurements, molar conductance and thermal gravimetric analysis (TGA).
All binary Cu(II) complexes exhibited octahedral geometry except Cu(II) complexes 3, 4 and 5 exhibited square planar geometrical arrangements. The ternary Cu(II) complexes revealed octahedral geometries.
Complexes of Ni(II) 11, Co(II) 12, Zn(II) 17 and Cd(II) 18 exist in tetrahedral geometries, meanwhile complexes of VO(IV) 13, Fe(III) 14 and Cr(III) 15, have octahedral geometries.
Complexes of Ce(III) 16 and UO2(II) 20 are pentagonal bipyramidal geometries.
It was found that the stretching frequency of C=Oaldehydic, in all complexes was shifted to lower values in the range 1671-1636 cm-1, in the infrared spectra.
Also, the 1H-NMR spectra of Zn(II) 17, Cd(II) 18 and UO2(VI) 20 revealed downshield shift of the aldehydic protons at δ 10.24, 10.35 and 10.40 ppm, respectively, indicating deshielding of these protons as a result of coordination.
The ligand and its metal complexes were screened for their antimicrobial activity against Staphylococcus aureus and Bacillus subtilis as Gram-positive bacteria, Escherichia coli and Salmonella typhimurium as Gram-negative bacteria, Candida albicans as yeast and Aspergillus fumigatus as fungal strains.
The antitumor activity of the HL ligand and its metal complexes were investigated against Ehrlich Ascites Carcinoma cell line (EAC) from ascetic fluid of the female Swiss albino mice. The tested complexes revealed variable activity towards the used cell.
To understand the nature of bonding of HL ligand to metal ions; semi-emperical (PM3) calculations were performed using Hyperchem 7.52 program. All theoretically probable structures of the free ligand (HL) and its complexes have been calculated using (PM3) method in gas phase to search for the most probable model building stable structure.
Structures of binary and ternary Cu(II) complexes 1-10 of the HL ligand
Structures of binary complexes 11-20 of the HL ligand.