Chemistry is the experimental and theoretical study of materials on their properties at both the macroscopic and microscopic levels.In a patent£¬ Recommanded Product: 1271-19-8, Which mentioned a new discovery about 1271-19-8
Titanocene and zirconocene complexes containing dendrimer-substituted cyclopentadienyl ligands – Synthesis and ethylene polymerization
This paper describes the synthesis of a series of titanium and zirconium metallocenes bearing one or two first-generation silane dendritic wedges as bulky substituents at their cyclopentadienyl rings. Wedges (R2R?SiCH2CH2)3SiCl [R = R? = Et (1); R = Ph, R? = Me (2)] were prepared by hydrosilylation of chlorotrivinylsilane with R2R?SiH. They were reacted with K(C5H5 and, subsequently, with KH to give K[(R2R?SiCH2 CH2)3Si(C5H4)] [R = R? = Et (3); R = Ph, R? = Me (4)]. The dendronized cyclopentadienides 3 and 4 were the starting materials for preparation of the mixed-ring titanocenes [{(R2R?SiCH2 CH2)3SiC5H4} (C5R?5)TiCl2] [R = R? = Et, R? = H (5), R? = Me (6); R = Ph, R? = Me, R? = H (7), R? = Me (8)] or the symmetrically substituted metallocenes [{(Ph2MeSiCH2 CH2)3SiC5 H4}2MCl2] [M = Ti (9), Zr (10)]. Cyclic voltammograms and catalytic behavior of all the new metallocenes in ethylene polymerization, using MAO as a co-catalyst, have been studied and compared to that of related non-dendritic complexes. Polyethylene polydispersities increase with the number of dendritic wedges in the catalyst, while activities decrease. Bimodal molecular weight distributions were clearly observed for the bis-dendritic titanocene 9. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Because enzymes can increase reaction rates by enormous factors and tend to be very specific, Recommanded Product: 1271-19-8, typically producing only a single product in quantitative yield, they are the focus of active research.you can also check out more blogs about 1271-19-8
Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI