Hydrosilylation of ferrocenylalkyne-dicobalthexacarbonyl complexes. Model reactions for the synthesis of organometallic dendrimers

摘要

Regio- and stereoselective hydrosilylation reactions of ferrocenylalkyne-dicobalthexacarbonyl complexes with HSiEt_3 or dendrimer Si[CH_2CH_2CH_2Si(CH_3) _2H]_4 have afforded the ferrocenylvinylsilanes [FcC(SiEt_3)=CH_2] (1), [FcC≡CC(SiEt _3)=C(H)R] [R = Fc (E-4), H (13), SiMe3 (Z-15)], and [(E)-FcC(H)=C(SiEt3)C≡CSiMe_3] (14) and the ferrocenylvinyl-functionalized carbosilane dendrimers Si[CH2CH 2CH2Si(CH3)2C(Fc)=CH 2]4 (3) and (Z)-Si[CH_2CH_2CH _2Si(CH_3)_2C{C≡CFc}=C(H)Fc]_4 (6). Characterization of all compounds by 1H, 13C{ 1H}, and 29Si{1H} NMR and IR spectroscopy, as well as mass spectrometry, supports their assigned structures. The molecular structures of compounds [{Co_3(CO)_9}(μ_3- CCH_2Fc)] (2), [C(O)C(Fc)=C(SiEt_3)C=C(H)Fc] (5), [{Co 2(CO)6}(μ,η~2-FcC≡CCCH)] (8), and [{Co_2(CO)_6}2(μ,I·2, I·2-FcCCCCSiMe_3)] (9) have been determined by single-crystal X-ray diffraction. The redox activity of the model diferrocenylalkynyl complex 4 and the corresponding octaferrocenyl dendrimer 6 has been examined by cyclic voltammetry