Living Anionic Polymerization of 1‐Adamantyl 4‐vinylphenyl ketone

Abstract

The anionic polymerization of 1-adamantyl 4-vinylphenyl ketone (1), a styrene derivative carrying an electrophilic carbonyl group, is carried out in tetrahydrofuran (THF). Although no polymerization of 1 occurs with sec-BuLi at −78 °C for 48 h, a polymeric product of 1 is obtained with diphenylmethyllithium in 10% yield under similar conditions. The resulting poly(1) has a very broad molar-mass dispersity (Đ M = M w /M n = 1.72) and a molecular weight higher than the calculated value based on the molar ratio of the monomer and initiator and the conversion. On the other hand, the polymerization of 1 with diphenylmethylpotassium or diphenylmethylcesium quantitatively proceeds in THF at −78 °C within 48 h to form the polymers with predicted molecular weights and narrow molecular weight distributions (M w /M n < 1.1). The stability of the propagating carbanion derived from 1 is demonstrated by the quantitative efficiency of the postpolymerization (sequential monomer addition). The reaction of the adamantyl ketone moieties of poly (1) with methylmagnesium iodide quantitatively proceeds in THF/diethyl ether at room temperature, indicating the high electrophilicity of ketone groups. The resulting poly(1) has a high glass transition temperature at 193 °C, indicating the effect of the bulky adamantyl substituent.

Living Anionic Polymerization of 4‐(1‐Adamantyl)‐α‐Methylstyrene

“…The incorporation of the bulky and rigid adamantyl framework to poly(α‐methylstyrene) as a pendant group induces the high T g value of poly( AdαMS ) at 274 °C, which is almost 110 °C higher than the parent poly(α‐methylstyrene). Thus, it is demonstrated that AdαMS is a new class of adamantyl‐substituted vinyl monomer giving the anionic living polymer, similar to the previous examples of AdS , Ad2S , N ‐(1‐adamantyl)‐ N ‐4‐vinylbenzylideneamine, and 1‐adamantyl 4‐vinylphenyl ketone …”

“…Recently, the living anionic polymerizations of styrenes carrying reactive moieties, N ‐(1‐adamantyl)‐ N ‐4‐vinylbenzylideneamine, and 1‐adamantyl 4‐vinylphenyl ketone are also achieved. The rigid and bulky adamantyl substituents effectively hindered any serious side reactions of the nucleophilic initiators and the propagating carbanion with the electrophilic CO and CHN groups and realized the living anionic polymerizations.…”

“…Thus, it is demonstrated that AdαMS is a new class of adamantyl-substituted vinyl monomer giving the anionic living polymer, similar to the previous examples of AdS, [27] Ad2S, [27] N-(1-adamantyl)-N-4-vinylbenzylideneamine, [41] and 1-adamantyl 4-vinylphenyl ketone. [42]…”

“…These T g values of the adamantyl‐substituted polystyrenes are significantly higher than that of the parent polystyrene ( T g = 100 °C). The highly symmetrical alicyclic adamantyl group has a negligible reactivity toward various chemical reagents, but it shows the drastic effect on enhancing the thermal properties of the resulting polymers …”

“…The highly symmetrical alicyclic adamantyl group has a negligible reactivity toward various chemical reagents, but it shows the drastic effect on enhancing the thermal properties of the resulting polymers. [29][30][31][32][33][34][35][36][37][38][39][40][41][42] Recently, the living anionic polymerizations of styrenes carrying reactive moieties, N-(1-adamantyl)-N-4-vinylbenzylideneamine, [41] and 1-adamantyl 4-vinylphenyl ketone [42] are also achieved. The rigid and bulky adamantyl substituents effectively hindered any serious side reactions of the nucleophilic initiators and the propagating carbanion with the electrophilic CO and CHN groups and realized the living anionic polymerizations.…”