Département de chimie moléculaire

A series of cyclic nitrones have been tested for their spin-trapping activity in the enhanced spin-capturing polymn. of styrene and in nitrone-mediated radical coupling reactions. rac-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-one was found to be the most efficient nitrone. The specific polystyrene macroradical addn. rate to this nitrone was detd. to be 8.0 × 10³ L.mol^-1.s^-1, which is by a factor of 10 higher than for previously studied compds. Via enhanced spin-capturing polymn., polymers in the range of oligomers to 30000 g.mol^-1 were obtained. A strong dependence of mol. wt. on monomer conversion was obsd., which can be explained by the high trapping rate. In nitrone-mediated radical coupling, almost ideal coupling of bromine-functional polymers was obtained and the successful introduction of the residual alkoxyamine functionality confirmed.