Monocyclopentadienyl complexes

The most active catalyst precursors are the monocyclopentadienyl complexes [Me2Si(C5Me4)(t-BuN)]LnN(TMS)2 [132]. Comparative reactivities for the IH of H2NCH2C(Me)2CH2CH=CH2 to give 2,4,4-trimethylpyrrolidine are given in Table 4-1. 

High-activity monocyclopentadienyl complexes, (II), containing indene were prepared by the authors (2) and used in the polymerization of ethylene. 

Reactions of CoCl2(PPh3)2 with TICp subsequently followed by treatment with [M(ArN3Ar)] (M = Cu1, Ag1) afforded CoCp(RN3R)(PPh3). These complexes are representatives of the very small number of paramagnetic monocyclopentadienyl complexes. ESR spectra indicate the presence of low spin Con in an environment of low symmetry (22).,0S... 

The reactivity of heteroleptic unsolvated monocyclopentadienyl complexes of type Cp Ln(OAr)2 towards alkali alkyls was studied in detail (Scheme 20) [209,210,220], For Cp Ce(OAr)2 slow and solvent dependent disproportionation to CpfCe(OAr) and Ce(OAr)3 was observed. Dialkylation is straightfor-... 

Monocyclopentadienyl complexes have also been used as active polymerization catalysts. Indeed, titanium monocyclopentadienyl metallocenes—the so-called constrained geometry catalysts —have been focal points of Dow s activity in this area. A typical example of such a catalyst is shown by the structure 6.24. 

---