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Abstract Design of macrocyclic and thiosemicarbazone ligands with various functionalities is a key factor in the advancement of the coordination chemistry resulting in (i) their ability to modify binding constants for use in selective metal extraction and as the therapeutic agents (ii) their a wide applications in pharmaceutical, analytical and industrial aspects e.g as antibacterial, antifungal, antimalarial, antineoplastic, anticarcinogenic, anti-HIV, anticancer, antitumour and antiviral activities and have biological activities. Their biological activities are considered to be related to their ability to form chelates with metals. For these applications, we are extending this field in synthesis novel metal complexes. Our study comprises five chapters: Chapter (I) gives a general introduction and literature survey for some important selected studies on related organic ligands and their metal complexes. Chapter (II) explains the practical method of preparation of ligands and different physicochemical method of analysis such as (elemental analysis, molar conductivity, 1H-NMR, mass, UV-Vis and FT-IR spectroscopy) for elucidation the structure of the metal complexes. The macrocyclic ligand was prepared via the interaction of etheylenediamine and ethylacetoacetate, while the thiosemicarbazone ligands were prepared by the condensation of thiosemicarbizide as starting material, with salicylaldehyde and 3- formyl chromone in the molar ratio 1:1 to afford the corresponding thiosemicarbazone ligands; H2L2 and HL3, respectively. Chapter (III) aims to production of macrocyclic ligand H2L1 and its complexes with Cd(II), Co(II), Cu(II) and Ni(II) ions in a molar ratio (1:1, ligand: metal ion). These complexes were characterized on the basis of elemental analysis, molar conductivity, 1H-NMR, mass, UV-Vis and FT-IR spectroscopy. All results confirmed that the prepared compounds have 1:1 metal-to-ligand stoichiometry, an octahedral configuration and the ligand behaves as a neutral tetradendate towards the metal ions. Thermal studies suggest a mechanism for degradation of the metal complexes as a function of temperature supporting the chelation modes, moreover, show the possibility of obtaining new complexes pyrolytically in the solid state which cannot be synthesized from the solution. The analytical results of the pyrolytically prepared complexes showed that the ligand behaves either as a neutral or dianoinic tetradentate ligand towards the metal ions. The binding of H2L1 and its copper(II) complex (3) to HS-DNA were studied. The experimental results suggested that the H2L1 and its copper(II) complex (3) bind to HS-DNA through an intercalative mode. Anti-tumor activiy of the H2L1 and its copper(II) complex were studied against Ehrlich Acites Carcinoma (E.A.C) and colon carcinoma cell lines growth. The H2L1 and its copper(II) complex possess remarkable activities. Chapter (IV) focuses on synthesis, characterization and thermal studies of binary and/or mixed complexes based on 2- (Hydroxybenzylidene) thiosemicarbazone (H2L2) with Cd(II), Cu(II), Ni(II) and Co(III) ions. The results obtained in this chapter were summarized as follows: - The changes in the selected vibrational absorption in FT-IR and 1H-NMR spectra of the Schiff base ligand upon coordination indicate that the ligand behaves as monoanoinic tridentate ligand manner with ONS donor sites via oxygen atom of the phenolic group, nitrogen atom of the azomethine group and sulfur atom of the thiocarbonyl group. - All binary complexes of Cu(II), Ni(II) and Co(III) ions have 1:1 metal-to-ligand stoichiometry, but in case of Cd(II) complex has 1:2 metal-to-ligand stoichiometry. - The analytical data of metal chelates indicate that the metal ions in case of all mixed ligand complexes are coordinated to one mixed ligand molecule (Gly, 2-Ampy or Phen) in addition to one H2L2 molecule. - In the mixed ligand complexes, glycine (Gly), acts as monoanonic bidentate ligand via the amino group and carboxylate group, while 2-aminopyridine (2-Ampy) acts as a neutral monodentate via the amino group but 1,10-phenanthroline has two pyridine rings nitrogen and acts as bidentate ligand. - All complexes have octahedral configuration, except binary Cu(II) complex (10) and Ni(II) complex (14), which have tetrahedral and square planer geometries, respectively. - Thermal studies suggest a mechanism for degradation of the metal complexes as a function of temperature supporting the chelation modes, moreover, show the possibility of obtaining new complexes pyrolytically in the solid state which cannot be synthesized from the solution. - The binary Cu(II) complex has a high binding affinity to HSDNA. Chapter (V) deals with preparation of new series of metal complexes of Cd(II), Cu(II), Ni(II), Co(III) and Fe(III) with Schiff base ligand, HL3, 3- formyl chromone thiosemicarbazone. In addition, the mixed ligand complexes were prepared by using glycine (Gly), 2-aminopyridine (2-Ampy), potassium thiocyanate (KSCN), 8-hydroxyquinoline (8-HOqu) and 1,10-phenanthroline (Phen) as secondary ligands. Also, new solid complexes were prepared pyrolytically in the solid state which cannot be synthesized from the solution by heating their mother complexes at the temperature at which the endo or exothermic peak was observed from DSC analysis. All synthesized compounds were identified and confirmed by elemental analyses, molar conductivity, UV-Vis, FT-IR and H-NMR spectroscopy and magnetic moment measurements as well as TG-DSC technique. The changes in the selected vibrational absorption in FT-IR and 1H-NMR spectra of the Schiff base ligand upon coordination indicate that the ligand behaves either as neutral or monoanonic ligand manner with ONS donor sites via the oxygen atom of the carbonyl group, the nitrogen atom of the azomethine group and sulfur atom of thiocarbonyl group. According to analytical data, all binary complexes of Cu(II), Ni(II), Co(III) and Fe(III) ions have 1:1 metal-to-ligand stoichiometry, but in case of Cd complex have 1:2 metal-to-ligand stoichiometry. Moreover, the analytical data of metal chelates indicate that the metal ions in case of all mixed ligand complexes are coordinated to one mixed ligand molecule (Gly or 2-Ampy or SCN or 8-HOqu or Phen) in addition to one HL3 molecule. In the mixed ligand complexes, glycine (Gly), acts as monoanonic bidentate ligand via the amino group and carboxylate group, while 2-aminopyridine (2-Ampy) acts as a neutral monodentate via the amino group but thiocyanate (SCN), acts as monoanonic monodentate ligand. In case of 8-hydroxyquinoline (8-HO-qu), behaves as monoanonic bidentate ligand via the amino group and hydroxy group but 1,10-phenanthroline (Phen) has two pyridine rings nitrogen and acts as bidentate ligand. Finally, the binary Cu(II) complex showed binding affinity to HS-DNA through intercalative. |