Please use this identifier to cite or link to this item: http://hdl.handle.net/1783.1/1004

Synthesis of optically active poly(silylethylene)s containing a stereogenic silicon center

Authors Wan, XH
Kwok, HS
Tang, BZ
Issue Date 1997
Source PROCEEDINGS OF THE FOURTH ASIAN SYMPOSIUM ON INFORMATION DISPLAY , 1997, p. 187-190
Summary Hydrosilylation of acetylene with a chiral silane, R-(+)-methyl-1-naphthyl-phenylsilane [R-(+)-Me-NpPhSi{*}H], in the presence of H2PtCl6 . xH(2)O proceeds with retention of configuration of the stereogenic silicon center and produces a chiral vinylsilane or silylethylene [S-(+)-MeNpPhSi{*}Vi] of high optical purity under mild condition (50 degrees C) in high chemical yield (85%), Anionic polymerizations of the chiral silylethylene monomer by an achiral initiator n-BuLi yield optically active polymers with [alpha](D)(20) Up to -28.1 degrees, while polymerizations of the racemic monomer by a chiral initiator n-BaLi/(-)-sparteine produce polymers with [alpha](D)(20) up to +275 degrees. Thus the sign of optical rotation of the polymers can be controlled by different combination of monomer and catalyst. Magnitude of the optical rotation can be "tuned'' by changing polymerization temperature with high temperature generally favoring random propagation. All the polymers have low polydispersity indexes (M-w/M-n, down to 1.02) or possess narrow molecular weight distributions, Spectroscopic characterization confirms the molecular structure of polymers to be poly(silylethylene), that is, a polyethylene main chain with a bulky methyl-1-naphthylphenylsilyl side chain. The polymers are thermally stable (onset temperature for weight loss in air: 380 degrees C), possess high glass transition temperature (T-g >380 degrees C), and may find a wide range of applications in the optical display systems.
Subjects
ISBN 962-8273-01-9
Language English
Format Conference paper
Access View full-text via Web of Science
View full-text via Scopus
Files in this item:
File Description Size Format
infodisp04.pdf 552851 B Adobe PDF