Soluble, highly conjugated derivatives of polyacetylene from the ring-opening metathesis polymerization of monosubstituted cyclooctatetraenes: synthesis and the relationship between polymer structure and physical properties

Using well-defined tungsten-based olefin metathesis catalysts, a family of partially substituted polyacetylenes have been synthesized via the ring-opening metathesis polymerization (ROMP) of monosubstituted cyclooctatetraenes (RCOT). These polymers are highly conjugated as evidenced by their visible absorption maxima, they are of high molecular weight as evidenced by gel permeation chromatography, and most members of the family are soluble in the as-synthesized, predominantly cis form. The polymers can be isomerized to the predominantly transform using heat or light. The rate of thermal isomerization was monitored by visible absorption spectroscopy. Polymers containing, in general, secondary or tertiary groups immediately adjacent to the main chain remain soluble in the trans form and are, in most cases, still highly conjugated.