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• 16753-20-1 bis(dimethylamido)titanium(IV) dichloride 

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Synthesis, structural features, and formation of organometallic derivates of C1-bridged Cp/amido titanium and zirconium CpCN-constrained geometry systems

A series of C1-bridged Cp/amido group 4 metal complexes [( CpCN )MX2] was prepared. The starting compound 6-tert-butylfulvene (7) was reacted with LiNHR (R = o-anisyl (a), p-anisyl (b), phenyl (c), or tert-butyl (d)) to yield the Li(C5H 4-CH(tBu)-NHR) compounds (8). Subsequent deprotonation with n-butyllithium, followed by transmetalation with Cl2Ti(NMe 2)2, yielded the ( CpCN )Ti(NR2) 2 complexes 10 (a-d). A second synthetic series started from 6-(dimethylamino)fulvene (11). The reaction with the LiNHR reagents led to addition followed by HNMe2 elimination to yield the respective imino-substituted cyclopen-tadienides Li(C5H4-CH=NR) (13). Addition of methyllithium to 13 gave the (Li+)2(C 5H4-CHMe-NR)2-, ( CpCN ) 2-, ligands (14). Transmetalation with Cl2Ti(NMe 2)2 subsequently yielded the corresponding μ-CHMe-bridged Cp/amido group 4 complexes 15 (a-c). Treatment with Me 2SiCl2 cleanly converted the ( CpCN )M(NR 2)2 complexes to the respective ( CpCN )MCl 2 systems [3a-d, 4a-c (Ti), 5a (Zr)]. These were transformed to the ( CpCN )M(CH3)2 complexes [μ-CHCMe 3: 17a-d (Ti), 19a (Zr), μ-CHMe: 18a-c (Ti)] and the (s-cis-supine-η4-butadiene)( CpCN )Ti systems 21a-d and 22b,c. With respect to X-ray structure analyses the (CpCN)MX2 systems must be regarded as more constrained than their ( CpSiN )MX2 analogues. The ( CpCN )MCl 2 and ( CpCN )M(CH3)2 complexes were used as catalysts for ethene homopolymerization and ethene/1-octene copolymerization. All systems gave active catalysts, but these were quite different in their catalytic performance when compared with the usually applied ( CpSiN )TiX2-derived catalysts. The ( CpCN )M catalyst activities and selectivities were very dependent on the specific activator components employed.