Indenyl‐Titanchloride: Ethen‐Polymerisation und Struktur‐Reaktivitäts‐Untersuchungen

Abstract

The halfsandwich complexes [(η 5 -C 9 H 7 )TiCl 3 ] (3a), [(η 5 -Me 3 Si-1-C 9 H 6 )TiCl 3 ] (3b), [(η 5 -Me-1-C 9 H 6 )TiCl 3 ] (3c), [(η 5 -Me 2 -4,7-C 9 H 5 )TiCl 3 ] (3d), [(η 5 -Me 3 Si-2-C 9 H 6 )TiCl 3 ] (3e), [(η 5 -Me 2 Ϫ1,3-C 9 H 5 )TiCl 3 ] (3f), [(η 5 -(CH 2 ) 3 Ϫ5,6-C 9 H 5 )TiCl 3 ] (4), and [(η 5 -(CH 2 ) 3 Ϫ1,7-C 9 H 5 )TiCl 3 ] (5) are accessible by reacting the in position 1 or 3 Me 3 Si-functionalized appropriate indenes with TiCl 4 . CG-TiCl 2 compounds (CG ϭ Constraint Geometry) can be synthesized by the subsequent reaction of Br-2-C 9 H 7 (6a), Br-2-Me 2 -1,3-C 9 H 5 (6b) and Br-2-(CH 2 ) 3 -5,6-C 9 H 5 (6c), respectively, with magnesium in presence of Me 2 SiCl 2 to give the respective Me 2 SiCl-functionalized indenes which further react with an excess of H 2 N t Bu to afford t BuHN-SiMe 2 -2-C 9 H 7 (8a), t BuHN-2-Me 2 -1,3-C 9 H 5 (8b) and t BuHNϪ2-(CH 2 ) 3 -5,6-C 9 H 5 (8c). The latter species produce on their consecutive reaction with n BuLi, [TiCl 3 ·3Thf] and PbCl 2 the titanium CG-complexes [(η 5 -SiMe 2 N t Bu-2-C 9 H 6 )TiCl 2 ] (9a), [(η 5 -Me 2 -1,3-SiMe 2 N t Bu-2-C 9 H 4 )TiCl 2 ] (9b), and [(η 5 -Me 2 SiN t Bu-2-(CH 2 ) 3 -5,6-C 9 H 4 )TiCl 2 ] (10). The same synthe- Chem. 2007, 633, 2242Ϫ2254 sis protocol allows the preparation of [(η 5 -Me 2 SiN t Bu-1-Me 3 Si-2-C 9 H 5 )TiCl 2 ] (12) a CG complex in which the Me 2 SiN t Bu unit is located in position 1. The polymerization of ethene by using 3Ϫ5 and 9Ϫ12 and MAO (MAO ϭ methylaluminoxane) as cocatalyst is described to show if a strong activity correlation between 3Ϫ5 and 9Ϫ12 exists. In order to optimize the catalytic activity of 3Ϫ5 the electronic (cyclic voltammetry, UV-Vis spectroscopy) and steric properties (Multiple Overlap Solid Angle) of these species were analyzed. Based on the obtained data, semi-empirical structure-activity models for 3Ϫ5 are proposed to obtain an optimized substituent pattern for the indenyl moiety. Substituents in position 1 or 4 of the appropriate indenyl π-perimeters show a strong bathochromic (ϩM) and electro-neutral to electro-negativ effect (0/-I).

Titanium, zirconium and hafnium

“…89 Replacing one methyl on each ring in [Cp* 2 Ti] by a SiMe 3 group greatly improves its stability, [Ti II (Z 5 97 (Indenyl)titanium(IV)chloride, [(Z 5 -C 9 H 7 )TiCl 3 ], and similar compounds of substituted indenyls have been synthesised and their ability as ethene polymerisation catalysts investigated. 98 [Cp*TiMe(O t Bu) 2 ] and [B(C 6 F 5 ) 3 ] react to form zwitterionic [Cp*Ti(O t Bu) 2 (m-Me)-B(C 6 F 5 ) 3 ], where all the methyl hydrogens interact agostically with Ti. 99 Thiuram disulfides, (R 2 NCS 2 ) 2 (R 2 = Me 2 , Et 2 , (CH 2 ) 5 ) oxidise [Ti(CO) 6 ] 2forming trigonal prismatic [Ti(CO) 4 (S 2 CNR 2 )] À .…”