A new class of noncoordinating anions are the carbosilane dendrimers with perfluoroarylborate end groups (see picture). They activate and stabilize metallocenes to give catalytic systems that polymerize olefins, such as ethene, propene, and 1‐hexene, with high activity.

The metallocene alkyne complexes [Cp 2 M(L)(η 2 -Me 3 SiC 2 R)] react with diisobutylaluminium hydride at room temp. by addition of HAl(iBu) 2 to yield the heterobimetallic complexes [{Cp 2 M}(µ-η 1 :η 2 -RCCSiMe 3 )(µ-H){Al(iBu) 2 }] [{Cp 2 M}: (η 5 -C 5 H 5 ) 2 Ti, R = Ph 1, R = SiMe 3 2; {Cp 2 M}: (η 5 -C 5 H 5 ) 2 Zr, R = SiMe 3 3; {Cp 2 M}: (ebthi)Zr, R = SiMe 3 4] {ebthi: rac-[1,2-ethylene-1,1Ј-bis(η 5 -tetrahydroindenyl)]}. Complexes 1−4

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Starting from zirconocene bis(trimethylsilyl)acetylene complexes Cp‘2Zr(L)(η2-btmsa) via the 2-vinylpyridine complexes Cp‘2Zr(2-vipy) a novel synthetic method for zirconocene difluoride and alkyl monofluoride complexes was elaborated. Examples with selected different ligand systems Cp‘2 [Cp2 = bis(η5-cyclopentadienyl); ebthi = 1,2-ethylene-1,1‘-bis(η5-tetrahydroindenyl); (thi)2 = bis(η5-tetrahydroindenyl); Me2Si(η5-C5H4)2 = dimethylsilylbis(η5-cyclopentadienyl); (i)2 = bis(η5-indenyl); ebi = 1,2-ethylene-1,1‘-bis(η5-indenyl); and Me2Si(η5-C9H10)2 = dimethylsilyl-1,1‘-bis(η5-tetrahydroindenyl)] were synthesized. In the series of these investigations new complexes (i)2Zr(THF)(η2-btmsa) (1), rac-(ebi)Zr(THF)(η2-btmsa) (2), (thi)2Zr(2-vipy) (3), Me2Si(η5-C5H4)2Zr(2-vipy) (4), (i)2Zr(2-vipy) (5), and rac-(ebthi)Zr(2-Ph-vipy) (6) were prepared as starting materials. Different methods for preparation of the zirconocene difluorides rac-(ebthi)ZrF2 (7), (thi)2ZrF2 (8), Me4C2(η5-C5H4)2ZrF2 (9), and Me2Si(η5-C9H10)2ZrF2 (10) and the monofluorides Cp2Zr(F)(CH2CH2-2-Py) (11), rac-(ebthi)Zr(F)(CH2CH2-2-py) (12), (thi)2Zr(F)(CH2CH2-2-py) (13), Me2Si(η5-C5H4)2Zr(F)(CH2CH2-2-py) (14), and Me2Si(η5-C9H10)2ZrF(Me) (15) are reported and compared. The molecular structures of the bis-η5-tetrahydroindenyl complexes 3, 8, and 13 were confirmed by X-ray crystal structure analysis.