First FT-Raman and 1H NMR comparative investigations in ring opening metathesis polymerization

Kinetics of ring-opening metathesis polymerization (ROMP) of exo,exo-5,6-di(methoxycarbonyl)-7-oxabicyclo[2.2.1]hept-2-ene, promoted by the Grubbs’ 1st generation precatalyst, has been effectively monitored by FT-Raman and NMR spectroscopy. Both techniques evidenced similar monomer conversions to be attained under the same reaction conditions. The present FT-Raman study provided information on the polymer steric configuration, the Raman bands at 1670 and 1677 cm−1 being specifically assigned to stretching vibrations of double bonds from the cis- and trans-polymer, respectively. The trans/cis ratio observed by FT-Raman parallels the corresponding result from 1H NMR. For the first time, a comparison was made on application of these complementary methods on the same ROMP reaction, evidencing their assets and disadvantages and reliability of FT-Raman.