ISSN:
1572-9028
Schlagwort(e):
organozirconium compounds
;
zwitterionic metallocenes
;
olefin polymerization
;
Ziegler–Natta catalysis
;
perfluorophenyl boranes
;
ion–ion interactions
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract The highly electrophilic boranes HB(C6F5)2 and B(C6F5)3 are effective reagents for generating a variety of zwitterionic olefin polymerization catalysts. The former borane can be used to incorporate Lewis acid activators into ancillary ligand structures via hydroboration of pendant olefinic functions; alternatively, direct reaction with simple organozirconocenes can lead to a family of hydridoborate stabilized girdle-type zwitterions where charge separation is minimal. The ethylene polymerization activity of these compounds is, in general, poor by virtue of the tight intramolecular ion pairing. More active zwitterionic catalysts can be generated through reaction of B(C6F5)3 with suitable organozirconium pre-catalysts. The solution and solid state structures of several of these compounds are discussed, highlighting the various mechanisms of stabilization found in the catalyst structures.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1019103531235
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