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.
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-Me(2)C(6)H(3) (1), 2,6-(i)Pr(2)C(6)H(3) (2), 2,6-Ph(2)C(6)H(3) (3), 2-FC(6)H(4) (4), 2,6-F(2)C(6)H(3) (5), C(6)F(5) (6); L = (O-2,4-Me(2)C(6)H(2)-6-CH(2))(2)(OCH(2)CH(2))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-Me(2)C(6)H(2)-6-CH(2))(2)(mu(2)-OCH(2)CH(2))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-(i)Pr(2)C(6)H(3) analogue (2), the C(6)F(5) analogue (6), and the 2,6-Me(2)C(6)H(3) analogue (1) showed moderate/notable catalytic activities for ethylene polymerization in the presence of MAO especially at 80-100 degrees C, whereas both the 2,6-Ph(2)C(6)H(3) analogue (3) and 2-FC(6)H(4) analogue (4) showed the negligible catalytic activities, clearly indicating that the activity was strongly affected by the terminal aryloxo substituents especially in the ortho-position.
Gurubasavaraj
Prabhuodeyara M
PM
Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101, Japan.
Nomura
Kotohiro
K