Synthesis of 1-ethyl-l,2,2-trimethyl-l,2-disilacyclobutane and its spontaneous polymerization and copolymerization with 1,1,2,2 -tetramethyl-1,2 -disilacyclobutane

• Published in: Russian chemical bulletin 2010-07, Vol.59 (7), p.1376-1380
• Main Authors: Gusel’nikov, L. E., Buravtseva, E. N., Ushakov, N. V., Lakhtin, V. G., Parshkova, L. A., Kuyantseva, N. A., Chernyshev, E. A.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Full Articles; Inorganic Chemistry; Organic Chemistry
• ISSN: 1066-5285; 1573-9171
• DOI: 10.1007/s11172-010-0249-2

Dehalogenation of 1-[(chloro)(ethyl)(methyl)silyl]-2-[chloro(climethyl)silyl]ethane with the alkali metal vapors gave l-ethyl-l,2,2-trimethyl-1,2-disilacyclobutane. Its spontaneous ring-opening polymerization at room temperature afforded an amorphous linear polymer with T g = −75 °C, M w = 454 200–512 800, and M w /M n = 1.87–2.82. According to NMR data, the backbone of the polymer consists of alternating monomeric units linked in the “head-to-tail” (SiMe 2 CH 2 CH 2 SiMeEtSiMe 2 CH 2 CH 2 SiMeEt) and “head-to-head” ways (SiMeEtCH 2 CH 2 SiMe 2 SiMe 2 CH 2 CH 2 SiMeEt) in a ratio of 1: 0.96. Spontaneous copolymerization of the above disilacyclobutane with 1,1,2,2-tetramethyl-l,2-disilacyclobutane gave partially crystalline copolymers with different glass transition and melting temperatures, depending on the ratio of the components in the reaction mixture. The compositions of the copolymers were examined by 1 H, 13 C, and 29 Si NMR spectroscopy.