الفهرس 
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Abstract
Summary
Chromones constitute one of the major classes of naturally occurring compounds and they are useful as biologically active agents. chromone derivatives also serve as intermediates to many products of pharmaceuticals, agrochemicals and dyestuffs. Metal complexes have attracted a significant interest as a result of their biological and pharmaceutical properties.
The present thesis aims to synthesize 2-aminochromone-3-carboxaldehyde (ACC) and condensing it with both semicarbazide hydrochloride and N4-phenylthiosemicarbazide in equimolar amounts to produce the corresponding tridentates NNO (HLa) and NOS (HLb), hydrazones, respectively. The chelating behavior of HLa and HLb, ligands were planned to react with Cu(II) metal ion with different anions; AcO–, NO3–, SO42– and Cl–, in absence and presence of secondary ligand (SCN-, 8-HQ and 1,10-phen), to form binary and ternary Cu(II)-chelates.
Structures of hydrazones and their Cu(II)-complexes were elucidated by elemental analysis, IR, 1H-NMR, 13C-NMR, mass, electronic spectra, as well as other physical tools such as magnetic susceptibility measurements, molar conductance and thermal gravimetric analysis (TGA).
The absorption and fluorescence characteristics of ACC, HLa and HLb were recorded in eleven different solvents with gradual increasing polarities at room temperature. The solvent effects on the fluorescence spectra of the reported molecules have shown solvatochromic behavior; bathochromic shifts on going from non-polar to polar solvents. This red shift refers to the presence of intramolecular charge transfer (ICT) interactions.
The ground and excited state dipole moments of ACC, HLa and HLb, were determined experimentally by solvatochromic shift method using Bilot–Kawski, Lippert–Mataga, Bakhshiev, Kawski–Chamma–Viallet and Reichardt’s microscopic solvent polarity functions and compared with those values obtained by TD-DFT (B3LYP/6-311G(d,p)) method. The large difference in dipole moments between electronically ground and excited states were found. Hence, the singlet excited state of the present molecules in polar solvent was more stabilized than the ground state.
The prepared binary Cu(II) complexes of HLa and HLb, ligands exhibited square planer and octahedral geometrical arrangements. The ternary Cu(II) complexes revealed octahedral geometries.
The HLa ligand is coordinated to copper(II) ion through its azomethine nitrogen, γ-pyrone oxygen and enolate oxgyen forming binary mononuclear complexes. However, HLb was coordinated through its azomethine nitrogen, γ-pyrone oxygen and thiolate sulfur forming binary mononuclear complexes.
Moreover, the ternary copper(II) complexes of HLa and HLb were obtained in molar ratios: 1:1:1 (M:L:Lʹ) by using secondary ligands (Lʹ) such as 8-hydroxyquinoline, 1,10-phenanthroline as well as potassium thiocyanate. The presence of coordinated water in metal complexes was confirmed by IR and TGA studies.
Molecular orbital calculations were carried out on the free ligands and their solid complexes using Gaussian 09 program on DFT method at B3LYP level. The calculated structural parameters data were correlated with some of the experimental data such as UV-VIS, IR and fluorescence spectra. Investigation of the structural parameters data and their correlations refers the following points.
1. The calculated heat of formation (ΔHf) as well as total energy, dipole moment, EHOMO, ELUMO and Egap of the free ligands conformers, predicted the more favorable tautomeric forms of the ligands.
2. ΔEgap of all complexes are smaller than that of their free ligands, indicates that the reactivity of complexes are higher than free ligands.
3. Generally, bond lengths of coordinating centers are longer than the corresponding in the free ligands (C=O & C=N)
4. The increasing of ΔEgap, leads to blue shift and decreases of frequency of (C-O) bond i.e. strong coordinating between oxygen and metal ion.
Applications of the ligands and some of their Cu(II)-complexes in various fields have included: fluorescence and biological submissions.
All the synthesized ligands and their Cu(II)-complexes may attend as potential photoactive provisions as indicated from their distinctive fluorescence. This new approach allows for the extraction of some new information not obtained from excitation and/or fluorescence spectroscopy for a single spectral scan. Complex 4 has the maximum probability of fluorescence emission, as it has the highest emission probability (ɛ) value (9.51x106). However, complex 6 has the minimum probability of fluorescence emission, ɛ value (3.53 x106). In contrast, the lifetime goes in the opposite direction. The Stokes-shifted emission spectra were measured for molecules of the current compounds in solution, varies in the range (56-245) nm. The lowest Stokes shift found for complex 6 (56 nm), whereas the highest Stokes shift found for complex 2 (245 nm). The complexes of HLb have higher Stokes shift than those of HLa. This promising optical properties of HLb complexes will be good candidates in the solar cell devices. The quantum yield values are found in the range 0.08– 0.223, indicate that the lowest quantum yield is ACC (φ = 0.08). However, the brightest fluorophore is the HLb compound (φ = 0.223), it is known that the higher quantum yield is desirable in most imaging applications.
The antimicrobial activity of the ligands and their Cu(II)- 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 and Aspergillus fumigatus as fungal strains.
Scheme 5. Representative structures of binary and ternary Cu(II) complexes 1-8 of the HLa ligan
Representative structures of binary complexes 9-16 of the HLb ligand