Polypentamethylnadimides obtained by Diels-Alder reaction

Abstract The reactions between benzylbromide or α,α′-dibromo- meta -xylene (DBMX) and sodium 1,2,3,4,5-pentamethylcycopenta-1,3-dienide (CpMe 5 ⊝ , Na ⊕ ) give only the expected pentamathylcyclopentadiene derivatives with a good yields. These products lead to endo isomer adducts via a Diels–Alder reaction with maleimide. New low molecular weight polypentamethylnadimides were obtained in this way from the Diels–Alder polymerization of bispentamethylcyclopentadiene monomers and commercial or synthetic bismaleimides. The polyadducts were characterised by size exclusion chromatography (SEC), matrix assisted laser desorption ionization-time of flight (MALDI-TOF), nuclear magnetic resonance (NMR) and thermogravimetric analyses (TGA). The low molecular weight was attributed to methyl steric hindrance. For the lowest molecular weight products, two different endcapped oligomers were observed.