Novel Hyperbranched Ferrocene-Containing Poly(boro)carbosilanes Synthesized via a Convenient A2 + B3 Approach

We report the synthesis of versatile hyperbranched ferrocene-containing poly(boro)carbosilanes (hb-PBCS) via a convenient A(2) + B-3 approach. Two types of hb-PBCS are obtained by the hydrosilylation of 1,1'-bis-(dimethylsilyl)ferrocene (A(2)) with trivinylmethylsilane (B-3) followed by modification with 9-borabicyclo[3.3.1]nonane (9-BBN) and by the hydroboration of 1,1'-bis(dimethylvinylsilyl)ferrocene (A(2)) with the borane-dimethyl sulfide complex (B-3), respectively. Size exclusion chromatography (SEC) results demonstrate that the well-soluble hb-PBCS possess appreciable weight-average molecular weight (M-w,M-SEC) up to 62 300 g/mol with the polydispersity index (PDI) of 1.95-4.51. The combined characterization by H-1-Si-29 heteronuclear multiple-bond correlation (HMBC), B-11 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 (alpha = 0.36-0.47) than that of their linear analogue (alpha = 0.69).