Indenyl ring

It can be concluded that significant differences in metal-carbon bond distances to coordinated olefins are not reflected in either the slip parameter or the barrier to rotation of the indenyl ring in this series of complexes. However, the relative strengths of the interactions between the [Rh( /5-indenyl)] fragment and OFCOT and COT are illustrated by some reactivity comparisons in Section VIII,F,2. 

The NMR spectrum of the La complex is similar to ionic NaC9H7 but the spectrum of the Sm complex showed a decrease in ionic character. The structure of Sm(Ind)3 consists of symmetrical coordination by indenyl rings with an average Sm-C distance of 2.75 A and the angle between Sm atoms and the normal to the planes of the indenyl rings is nearly 120°. There is no preference in bonding to the electron-rich C-l position thus indicating the bonds to be primarily ionic in nature [225]. 

SCHEME 3. Simplified polymerization mechanism showing the stereoselective shift of the enolate ring of 242 away from the indenyl ring (L) system upon addition of MMA to yield 243. An Sjv 2-type reaction of 244 with MMA to yield 243 might also be possible... 

Ind-amido titanium complexes with o -alkenyl functions in position 2 of the indenyl ring have been synthesized and characterized. After activation with MAO, these complexes were used as homogeneous and heterogeneous catalysts for the homopolymerization of ethylene and propylene and the co-polymerization of ethylene and 1,7-octadiene.406 A series of alkyl-, u -alkenyl-, and u -phenylalkyl-substituted Cp- and Ind-amido dichloro titanium complexes have been synthesized and characterized. The cj-phenylalkyl-substituted complexes react with LiBu to give metallacycles via a CH activation reaction on the ortho-position of the phenyl group (Scheme 305).741 742 After activation with MAO, these complexes catalyze ethylene polymerizations. The substituents on the aromatic system influence the polymerization activity of the catalysts and the properties of the polyethylene. The u -alkenyl-substituted catalysts show self-immobilization in ethylene polymerization. 

The Ind-amido complex (2-C9F[6SiMe2NBut)TiCl2 with the silyl bridge in position 2 on the indenyl ring has been synthesized. Its molecular structure and its use as a single site catalyst in the co-polymerization of ethylene and propylene is reported.743... 

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