Pakistan Research Repository

Synthesis Characterization and Catalytic Activity of Transition Metals Complexes

Asma, Maliha (2010) Synthesis Characterization and Catalytic Activity of Transition Metals Complexes. PhD thesis, Quaid-i-Azam University, Islamabad.

[img]HTML
15Kb

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.

Item Type:Thesis (PhD)
Uncontrolled Keywords:Synthesis, Characterization, Catalytic, Activity, Transition, Metals, palladium, Complexes, quinoxalinyl, oligomerization,
Subjects:Physical Sciences (f) > Chemistry(f2)
ID Code:6696
Deposited By:Mr. Javed Memon
Deposited On:18 Jul 2011 15:21
Last Modified:18 Jul 2011 15:21

Repository Staff Only: item control page