Generation of Homogeneous (sp³-C₁)-Bridged Cp/Amido and Cp/Phosphido Group 4 Metal Ziegler−Natta Catalyst Systems

How to synthesize a constrained geometry catalyst (CGC) – A survey

“…Dianionic ethylene-bridged ligand systems may be formed by milder deprotonation with NEt 3 before subsequent reaction with TiCl 4 gives the corresponding complexes in high yields [23] (Scheme 6). In the case of methylene-bridged CGCs, bis(amido)dichlorocomplexes such as Zr(NEt 2 ) 2 Cl 2 (THF) 2 and Ti(NMe 2 ) 2 Cl 2 proved to be successful [24][25][26].…”

“…Silylene- [27] and methylene- [25,28] bridged Cp phosphido ligands were successfully transformed in the same way, while other attempts utilizing metal tetrachlorides or metallation reactions failed. The metathesis method was also applicable for Cp analogues such as the fluorenyl- [29], cyclohexadienyl- [30] and boratabenzene [31] -amido catalysts.…”

“…Only in the case of elongated C2-and C3-bridges was it possible to obtain monomeric ''CpC n O'' MX 2 complexes [39,57,58]. CpSiP-and CpCP-catalysts were reported only recently by Erker et al [25,27,28]. In contrast to CpSiN-complexes the phosphido analogues reveal a distorted geometry, due to the chiral, non-planar coordination mode of the phosphorus atom.…”

Synthesis and characterization of phosphorous-bridged bisphenoxy titanium complexes and their application to ethylene polymerization

“…Moreover, Fujita and Coates independently reported that fluorine substituted phenoxy-imine titanium complexes catalyze syndiospecific living polymerization of propylene [13]. We have been interested in phosphorous incorporated complexes, whose unique properties are recently reported for phenoxyimine [14] and half-metallocenes of group 4 metals [15] as well as rare earth metals [16]. Herein we report the synthesis of phosphorous-bridged bisphenoxy titanium complexes and their catalytic behavior for ethylene polymerization.…”

Polymerizable group 4 ansa-cyclopentadienyl-amido catalysts for the copolymerization of ethylene with 1-octene

“…The results are summarized in Table 2. Although we could not isolate 7b, the diamido zirconium 6b can still be transformed to active species using excess MAO based on the previous results [14]. This is also true for 6a and 7a which gave similar copolymer products in terms of molecular weight, molecular weight distribution and comonomer content, except for the lower activity obtained with 6a ( Table 2, entry 1 and 3).…”