Synthesis and anionic polymerization of silacyclobutanes bearing naphthyl or biphenyl groups at the 3-position

Synthesis and anionic polymerization of 1,1-dimethyl-3-(1-naphthylmethyl) silacyclobutane (3-NMSB), 3-(4-biphenylmethyl)-1,1-dimethylsilacyclobutane (3-BMSB), and 1,1-dimethyl-3-(1-naphthyl)silacyclobutane (3-NSB) were investigated. 3-NMSB, 3-BMSB, and 3-NSB were synthesized by hydrosilation of 3-chloro-2-(1-naphthylmethyl)-1-propene, 3-chloro-2-(4-biphenylmethyl)-1-propene, or 3-chloro-2-(1-naphthyl)-1-propene with chlorodimethylsilane followed by a treatment with magnesium, respectively. Butyllithium-induced polymerization of 3-NMSB, 3-BMSB, and 3-NSB under a condition of [M](0)/[I](0) = 20/1 [M](0) and [I](0) are the initial concentrations of monomer and initiator) in THF at -78 degreesC was carried out. Poly(3-NMSB) (M-n = 3500, M-w/M-n = 1.21), poly(3-BMSB) (M-n = 4600, M-w/M-n = 1.09, and poly(3-NSB) (M-n = 3200, M-w/M-m = 1.16, where M-n and M-w were estimated by GPC using polystyrene as standards) were obtained. By differential scanning calorimetry (DSC) measurements, glass transition temperatures (T-g)s were determined at 17 degreesC for poly(3-NMSB), 28 degreesC for poly(3-BMSB), and 39 degreesC for poly(3-NSB).