N-heterocyclic carbenes:: Versatile reagents for postpolymerization modification

The coupling reaction between N-Heterocyclic Carbenes (NHC) and azides to afford triazenes has been shown to be a practical and versatile method for the postpolymerization modification of polyolefins. It is also shown that polystyrenes containing pendent azido moieties may be quantitatively converted to the triazeno-functionalized derivatives using a commercially available NHC. It was found that the catalyst free NHC azide coupling reaction was rapid and quantitative at ambient temperature, manifesting in a linear correlation between polymer modification and quantity of NHC added. It was also found that heating NHC modified poly(p-azidomethylstyrenes) resulted in nitrogen extrusion and transformed pendent triazeno moieties to their respective guanidines.