Funktionalisierte Siliciumverbindungen mit o-Tetramethyl- und o-Pentamethylcyclopentadienylalkyl-Liganden: Molekulare Bausteine zur Darstellung von Metall-haltigen Polymeren *

Peralkylated cyclopentadiene systems of the type Me,C,(CH,),Si(Me),Y,_,, which possess cyclopentadiene units connected with a functionalized silane fragment by an alkylidene spacer group, are prepared via two routes. As an example of the first route, the disiloxane [Me,C,(CH,),Si(Me),],O (2) has been synthesized from the corresponding iodo compound [I(CI-Iz),Si(Me),],O (1) by reaction with Me&K. The trichlorosilane MesCs(CH,)$iCIs (41, as an example of a compound prepared via the second route, has been isolated after hydrosilylation of l-prop-Zenyl-l,2,3,4,5-pentamethylcyclopenta-2,4-diene (3) with HSiCI,. Both synthetic methods are also suitable for the preparation of partly alkylated cyclopentadiene systems of the type Me,HC,(CH,),,Si(Me),,,Ys_~. Thus the w-iodoalkyltriethoxysilanes I(CH,I,Si(OEt), (n = 1, 2, 3) react with Me,HC,K to give the corresponding o_(tetramethylcyclopentadienyl)alkyl-triethoxysilanes 5-7. Compounds 5-7 consist of a mixture of isomers; the ratio between isomers having an allylic or vinylic hydrogen atom at the cyclopentadiene ring depends on the spacer length. Isomeric mixtures of the 4_(tetramethylcyclopentadienyl)butyyl-silanes of the type Me,HCs(CH,),Si(Me),CIs_, (m = 1, 2, 3) (8-10) with an allylic hydrogen atom at the cyclopentadiene ring have been prepared by hydrosilylation of l-but-3-enyl-2,3,4,5tetramethylcyclopentadiene. The silane fragment in the alkylated cyclopentadiene systems 2 and 4-10 can be modified further. As examples hydrolysis, alcohoiysis, reductive coupling, heterogenisation and polycondensation reactions are described. Following theses procedures the corresponding silanol 12 and disiloxane 13 have been prepared as well as the alkoxysilanes 14-17, the disilane 18 and the functionalized silicagels 19 and 20. Compounds 2, 4-10 and 12-20 serve as a “pool” for the preparation of transition metal complexes. The dicarbonyl cobalt compound 21 has been synthesized by reaction of 8 with Co,(CO)s. Reaction of 16 with K and FeCl, gives the corresponding ferrocene derivative 22. The q4-bound PtfIDand Pd(II)-complexes 23-27 have been prepared by reaction of the functionalized Si-O-compounds 2, 13, and 19-20 with [PtCl,(Ethylen)l, and PdClrfPhCN),, respectively.