Dimeric model, anionic polymerization

Subsequently, the anionic polymerization of BFl with PhLi as the initiator allowed us to isolate and characterize monomer and dimer species and the corresponding polymer (poly-BFl-AP). A careful smdy performed by NMR spectroscopy on the monomers and dimers, considered as model compounds, was of a great help in the understanding of the poly-BFl structure, also providing evidence on 3t-stacked nature for the polymer [23]. 

The construction of a model (Table 5.50) can therefore start from the SiO ions present in the orthosilicate eomposition (66% M Op. With a decrease in the molar fraction of the size of the anions must increase to maintain the stoichiometry. One can consider that there is a joining up, or polymerization, of the tetrahedral SiO monomers. For example, the dimer Si20 (Fig. 5.73) could be obtained thus... 

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