Search results for "Olefin polymerisation"
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DFT analysis of titanium complexes with oxygen-containing bidentate ligands
2003
Strength of the TiO co-ordinate bond in several titanium complexes with bidentate ligands has been investigated by means of DFT. Mutual interaction of particular donors and their influence on Lewis acidity of the central atom have also been studied. The energy of ligand binding ranges from −19 to −454 kJ/mol, depending on the kind of donors. Calculations confirm that a strong donor, alkoxide anion, co-ordinatively saturates the titanium and makes binding of new ligands less exoenergetic. On the contrary, two oxygen atoms of similar donor number do not have much influence on each other. Strength of the TiO bonds in titanium complexes with certain oxygen-containing bidentate ligands has bee…
Ziegler–Natta catalysts based on vanadium halides: a DFT study
2003
Abstract Ziegler–Natta ethylene insertion into the carbon–metal bond for a number of fragments containing vanadium on different oxidation states as well as the halogen ligands has been studied by means of DFT. It is shown that the complexation and insertion energies are strongly influenced by the charge on the transition metal atom and, to some extent, by the electronegativity of the halogen atom. Complexation energy varies in the range −129 to −159 kJ/mol for charged species and −64 to −77 kJ/mol for neutral ones. Insertion energy follows a similar pattern and ranges from −28 to −62 and −82 to −100 kJ/mol, respectively. The calculated values are compared with the experimental results and d…