الفهرس 
Chapter I. IntroductionOnly 14 pages are availabe for public view
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Abstract
The present thesis comprises of three main chapters in addition to Arabic and English summaries. The data are collected in (21 Tables) and
represented in (62 Figures), (10 Schemes) as well as (161 References).
The First Chapter: Introduction
This chapter concerned with a scientific literature survey on
dehydroacetic acid derivatives, pyrazolopyridine compounds and 2-thiobarbituric acid and their chelates as well as their biological activity.The Second Chapter: Experimental This part describes the preparation of Schiff base ligand (HL1), (Z)-3-(1-
((4,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-yl)imino)ethyl)-4-hydroxy-
6-methyl-2H-pyran-2-one which is prepared from condensation of 4,6-
dimethyl-1H-pyrazolo[3,4-b]pyridin-3-amine with dehydroacetic acid
with (1:1) molar ratio. Also, it describes synthesis of azodye ligand (H3L2),
(E)-5-((4,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-yl)diazenyl)-2-thioxo
dihydropyrimidine-4,6(1H,5H)-dione which is resulted from coupling of
diazotization of 4,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-amine with 2-
thiobarbituric acid with (1:1) molar ratio. HL1 ligand reacts with Co(II),
Pd(II), Fe(III) chloride and Cu(II) salts (chloride, bromide, sulphate and
perchlorate) with different molar ratios. Also, (H3L2) ligand reacts with
Co(II), Ni(II), Cu(II), Pd(II), Fe(III), Ru(III).
The structure of ligands and their metal complexes were elucidated by
elemental analyses, spectral techniques (IR, UV–Vis, 1H NMR, ESR, Xray diffraction and mass spectra for the ligands), magnetic susceptibility,
molar conductivity and thermogravimetric studies. Finally, the biological
activity (antioxidant and antibacterial) of the prepared ligands and some of
their metal complexes was investigated.
The Third Chapter: Results and Discussion
This chapter concerned to discuss the obtained results illustrating the
chemical formula, mode of bonding and geometrical structure for all
systems.
(I) Part (A) concerning Schiff base ligand )HL1(
The date proved that:
The complexes are formed with different stoichiometries (1:1), (1:2)
and (2:3) (M:L).
The ligand HL1 coordinates in Co(II), Cu(II), Pd(II) chloride and
CuSO4 complexes as a monobasic tridentate ONN moiety via the
oxygen atom of the deprotonated phenolic OH, the nitrogen atoms of
the azomethine and the imine groups in pyrazolopyridine ring. While,
it behaves as a neutral/monobasic bidentate in CuBr2, Cu(ClO4)2 and
FeCl3 complexes, chelates via oxygen and nitrogen atoms of enolic OH
and azomethine groups.
The complexes separated from CuCl2, CuBr2 and FeCl3have octahedral
structure. While, CoCl2 and CuSO4 complexes have triagonal
bipyramidal and square pyramidal geometries, respectively. However,
Cu(ClO4)2 and PdCl2 complexes have square planar structure.
(II) Part (B) concerning azodye ligand (H3L2)
The results showed that:
The complexes derived from azodye ligand (H3L2) have mononuclear
structure with (1M:2L) molar ratio for all complexes except Pd(II)
complex has (1M:1L) molar ratio. The molar conductivity values
reveal that all complexes have nonelectrolytic nature.
The azodye ligand coordinated with all metal ions (except Fe(III) and
Ru(III)) in neutral keto-thione form via oxygen and nitrogen atoms of
thiobarbituric acid carbonyl and azo groups. But, in Fe(III) and Ru(III)
complexes one of the ligands behaved as neutral bidentate in ketothione form and the other one acted as monobasic bidentate species.
All complexes of H3L2 ligand have octahedral geometry except Pd(II)
complex possess square planar structure.
TG/DTG studies confirmed the chemical formula for all prepared metal
complexes of HL1 and H3L2 ligands and established the thermal
decomposition processes ended with the formation of metal or metal
oxides contaminated with carbon residue.
An axial electron spin resonance spectra were suggested for all
prepared Cu(II) complexes pointing to 2B1g as a ground state.
In vitro antibacterial and antioxidant activities were performed for HL1
and H3L2 ligands and some of its metal complexes. The biological
studies indicate that CuBr2 and CuCl2 complexes has better
antibacterial activity compared to the ligand and the other complexes.