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Title of Thesis

Synthesis Characterization and Catalytic Activity of Transition Metals Complexes

Author(s)

Maliha Asma

Institute/University/Department Details
Department of Chemistry / Quaid-i-Azam University, Islamabad
Session
2010
Subject
Inorganic/Analytical Chemistry
Number of Pages
129
Keywords (Extracted from title, table of contents and abstract of thesis)
Synthesis, Characterization, Catalytic, Activity, Transition, Metals, palladium, Complexes, quinoxalinyl, oligomerization,

Abstract
In this study, different series of chromium and palladium catalysts were synthesized. Chromium (111) complexes were synthesized containing N*N*N tridentate 2- quinoxalinyl-6-iminopyridine. Seven different ligands used to prepare these catalysts are 2,6-diethyl; 2,6-dimethyl; 2,6-diisopropyl; 2,6-dichloro; 2,6- difluoro; 2,6- dibromo; 2, 4, 6-trimethyl-N-(I-(6-(quinoxalin-3-yl)pyridin-2-yl)ethylidene)benzenamine. These complexes were characterized by elemental analysis, Infrared spectroscopy (IR) and single crystal X-ray analysis. When these catalysts were subjected to oligomerization and polymerization of ethylene with modified methylaluminoxane (MMAO) as co-catalyst, they showed high catalytic activity. The catalytic activity results are influenced by steric and electronic properties of the ligands in the catalyst complexes as well as the reaction parameters.
In one series, palladium catalysts were synthesized using different mixed donor ligands (substituted anilines and substituted phosphines). These catalysts were characterized by IR, multinuclear (1H, 13C and 31P) NMR and single crystal X-ray analysis, showing that the catalysts maintain the same geometry in the solid as well as in the solution phase. Single crystal analyses revealed that these catalysts exhibit a distorted square planar coordination geometry around the Pd center. The catalytic activity studies revealed that these catalysts exhibit moderate activities for ethylene oligomerization when these were used in combination with MAO as co-catalyst. In another series, six palladium complexes were prepared containing 2,9-dimethyl-1,10-phenanthroline and different substituted phosphines [triphenylphosphine, tris-o-tolylphosphine, tris-m-tolylphosphine, tris-p-tolylphosphine, cyclohcxyldiphenylphospilinc, diphenyl-2- pyridylphosphine. tricyclohexylphosphine, diphenyl (2-methoxyphenyl) phosphine). These complexes were characterized by Fourier transform infrared spectroscopy (FT-IR), multinuclear (1H, 13C, 31P) NMR and single crystal X-ray analysis. Single crystal X-ray studies confirm a distorted square planar coordination geometry. All these results fully support that these complexes exhibit the same geometry in the solid and solution phase.
Keeping in view the industrial importance of copolymers, the copolymerization of ethylene with different polar co-monomers such as ally) ethyl ether and ally) bromide was investigated. For this purpose Pd(PO-0Me)Me(Py) and base-free Pd(PO-OMe)Me were employed. The obtained copolymers were characterized by multinuclear ID (1H, 31C, DEPT-135) NMR and 2D- (COSY, HMQC) NMR. All results confirm the incorporation of the ally1 co-monomer into the main backbone of polyethylene.

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8,138 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 CONTENTS

 

 
308 KB
2

1

INTRODUCTION 1
1,848 KB
3 2 EXPERIMENTAL 28
2,064 KB
4 3 RESULTS AND DISCUSSION 56
1,744 KB
5 4 ETHYLENE OLIGOMERIZATION, POLYMERIZATION AND COPOLYMERIZATION 83
1,303 KB
6 5 CONCLUSION AND FUTURE WORK 101
259 KB