Alternating Ring-Opening Metathesis Polymerization Copolymers Containing Charge-Transfer Units

Alternating copolymers derived from the ring-opening metathesis polymerization (ROMP) of functionalized cyclobutene esters (CBEs) and cyclohexenes (CHs) are described. The copolymer poly­(CBE-<i>alt</i>-CH)_<i>n</i> contains alternating side chains based on dialkoxynaphthalene (DAN) and pyromellitic dianhydride (PDI). Characterization by UV–vis spectroscopy showed that the copolymers exhibit an increase in charge-transfer intensity in comparison to previously reported alternating copolymers. The bulky side chains inhibit backbiting during the polymerization and allow for enhanced control over the polymerization in comparison to copolymers functionalized with linear alkyl groups