Precise synthesis of monosubstituted polyacetylenes using Rh complex catalysts. Control of solid structure and π-conjugation length
1999; Wiley; Volume: 200; Issue: 2 Linguagem: Inglês
10.1002/(sici)1521-3935(19990201)200
ISSN1521-3935
AutoresMasayoshi Tabata, Takeyuchi Sone, Yoshikazu Sadahiro,
Tópico(s)Catalysis for Biomass Conversion
ResumoStereospecific polymerization of monosubstituted acetylenes was successfully performed using a Rh complex, [Rh(norbornadiene)Cl]2, as a catalyst, and the resulting polyacetylenes were characterized in detail by 1H NMR, ESR, laser Raman, diffuse reflective UV, and wide-angle X-ray diffraction. The Rh complex was found to yield selectively the cis-transoid isomer even at room temperature in high yields when alcohol or triethylamine was used as the solvent. Additionally, the resulting cis-polyacetylenes were found to form a pseudohexagonal, columnar self-assembly or superstructure. Further compression of the cis-polymers induced cis-trans isomerization even at room temperature under vacuum, breaking rotationally the cis-C=C bonds and, thus, giving π-radicals as the origin of magnetic properties.
Referência(s)