|387. Kong, J.; Schmalz, T.; Motz, G.; Müller, A.H.E.: Novel Hyperbranched Ferrocene-Containing Poly(boro)carbosilanes Synthesized via a Convenient A2+B3 Approach, Macromolecules 44(6), 1280 (2011) -- DOI: 10.1021/ma1029086|
We report the synthesis of versatile hyperbranched ferrocene-containing poly(boro)carbosilanes (hb-PBCS) via a convenient A2 + B3 approach. Two types of hb-PBCS are obtained by the hydrosilylation of 1,1′-bis(dimethylsilyl)ferrocene (A2) with trivinylmethylsilane (B3) followed by modification with 9-borabicyclo[3.3.1]nonane (9-BBN) and by the hydroboration of 1,1′-bis(dimethylvinylsilyl)ferrocene (A2) with the borane−dimethyl sulfide complex (B3), respectively. Size exclusion chromatography (SEC) results demonstrate that the well-soluble hb-PBCS possess appreciable weight-average molecular weight (Mw,SEC) up to 62 300 g/mol with the polydispersity index (PDI) of 1.95−4.51. The combined characterization by 1H−29Si heteronuclear multiple-bond correlation (HMBC), 11B nuclear magnetic resonance (NMR), and triple-detection SEC (triple-SEC) confirms the remarkable hyperbranched architecture of hb-PBCS with degrees of branching (DB) between 0.47 and 0.79. The Mark−Houwink−Sakurada exponents of hb-PBCS obtained from triple-SEC are significantly lower (α = 0.36−0.47) than that of their linear analogue (α = 0.69).