Anionic synthesis of poly(9-methyl-9-trimethylsilyl-2-vinylfluorene) (PMSVF). Spontaneous deprotection-protonation of PMSVF with potassium methoxide/methanol gives poly(9-methyl-2-vinylfluorene)

摘要

The BuLi or potassium naphthalide initiated polymerization is described of 9-methyl-9-trimethylsilyl-2-vinylfluorene (MSVF) in tetrahydofuran at -78 degreesC. The purification is described of this monomer and of 9,9-dimethyl-2-vinylfluorene (DMVF) by polystyrene (PS) beads that are functionalized with 9-alkylfluorenyllithium groups that act as both scavengers and indicators. In both Li and K ion mediated polymerizations of MSVF, narrow molecular weight distribution PMSVFs are obtained. For the Li ion mediated termination of the living polymer by methanol, the PMSVF is readily isolated. However, in the presence of potassium ion a spontaneous and catalytic deprotection occurs of the trimethylsilyl group by potassium methoxide (MeOK). This reaction appears to be prevented in the case of the Li ion by strong ion pair or ionic aggregate interactions of MeOLi. [References: 22]