Pressure-induced cis to trans isomerization of poly(para-methylthiophenylacetylene) prepared by a [Rh(norbornadiene)CL]_2 catalyst. A raman, UV, and esr study

摘要

In our previous articles we reported that monosubstituted acetylenes such as phenylacetylene derivatives can be stereospecifically polymerized in the presence of a Rh complex, [Rh(norbornadiene)Cl]_2, [Rh(NBD)Cl]_2, when triethylamine (TEA) or alcohol is used as the polymerization solvent in order to selectively produce the helical cis-transoid isomer in high yields under mild conditions. In addition, we also reported that TEA or alcohol solvent works as the cocatalyst in the polymerization. We also found that poly(p-methoxyphenylacetylene), (PpMOPA) prepared with the Rh complex, can be isomerized from the cis to the trans forms, when the cis-polymer powder was subjected to pressure at room temperature.