Premium
Synthesis and Application of Ring‐Substituted Analogues of the [4‐(η‐Cyclopentadienylidene)‐4,7,7‐trimethyl‐4,5,6,7‐tetrahydro‐η 5 ‐indenyl]‐ZrCl 2 Ansa‐Metallocene System
Author(s) -
Psiorz Christian,
Erker Gerhard,
Fröhlich Roland,
Grehl Matthias
Publication year - 1995
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19951280407
Subject(s) - metallocene , chemistry , dilithium , cyclopentadienyl complex , propene , sandwich compound , ring (chemistry) , polymer chemistry , medicinal chemistry , stereochemistry , polymerization , catalysis , organic chemistry , x ray crystallography , deprotonation , polymer , ion , physics , diffraction , optics
Reaction of the 2,5‐hexanedione‐derived bisfulvene 1 with RLi reagents (R = phenyl or n ‐butyl) yields the ring‐closed [4‐(cyclopentadienylidene)‐7‐R‐4,7‐dimethyl‐4,5,6,7‐tetrahydroindenyl]dilithium reagents 3 . Their reaction with MCl 4 (M = Ti, Zr, Hf) gives the corresponding ansa‐group‐4‐metallocene dichloride complexes 4, 6 , or 7 . In a similar way the [7‐allyl‐4‐(η‐cyclopentadienylidene)‐4,7‐dimethyl‐4,5,6,7‐tetrahydro‐η 5 ‐indenyl]metal dihalides (M = Ti, Zr) ( 6d, 4d ) are prepared. Two diastereomers are formed in most cases, some of which could be separated. The five representative examples cis ‐ and trans ‐ 4c , trans ‐ 4d , cis ‐ 6c , and trans ‐ 7c of these complexes were characterized by X‐ray diffraction. All these six‐membered ring‐annulated C 1 ‐bridged ansa‐metallocene dichlorides exhibit extremely small D1ZrD2 angles (D1 and D2 denote the centroids of the cyclopentadienyl rings) of 116.5°, i.e., they are characterized by a very open bite of the bent metallocene wedge. The homogeneous Ziegler‐type catalysts derived from these ansa‐zirconocenes by activation with methylalumoxane have high activities and all produce low‐molecular mass atactic polypropylenes or propene oligomers.