Synthesis and Structural Analysis of Titanatranes Bearing Terminal Substituted Aryloxo Ligands of the type [Ti(OAr){(O-2,4-Me2C6H2-6-CH2)(2)(OCH2CH2)N}](n) (n=1, 2): Effect of Aryloxo Substituents in the Ethylene Polymerization

摘要

A series of titanatranes containing both chelate bis(aryloxo)-(alkoxo)amine and the terminal aryloxo ligands of type [Ti(OAr)(L)](n) [n=1 or 2, Ar=2,6-Me2C6H3 (1), 2,6-(Pr2C6H3)-Pr-i (2), 2,6-Ph2C6H3 (3), 2-FC6H4 (4), 2,6-F2C6H3 (5), C6F5 (6); L=(O-2,4-Me2C6H2-6-CH2)(2)(OCH2CH2)N)] have been prepared, and their structures (1, 3-6) were determined by X-ray crystallography. The ortho-substituents in the terminal aryloxo ligand directly affect the structure in the solid state; the structures of 1 - 3 possessed monomeric form and fold a distorted trigonal bipyramidal geometry around Ti, whereas the structure of 4-6 were of dimeric form and fold a distorted octahedral around Ti bridged with oxygen in the alkoxo arm expressed as [Ti(OAr){(O-2,4-Me2C6H2-6-CH2)(2)(mu(2)-OCH2CH2)N)}](2). The Ti-O(Ar) bond distances and the Ti-O-C(Ar) bond angles are highly influenced by the terminal aryloxo, substituents especially in the ortho-position. The 2,6-(Pr2C6H3)-Pr-i analogue (2), the C6F5 analogue (6), and the 2,6-Me2C6H3 analogue (1) showed moderateotable catalytic activities for ethylene polymerization in the presence of MAO especially at 80-100 degrees C, whereas both the 2,6-Ph2C6H3 analogue (3) and 2-FC6H4 analogue (4) showed the negligible catalytic activities, clearly indicating that the activity was strong affected by the terminal aryloxo substituents especially in the ortho-position.